Progesterone for the Prevention of Preterm Birth: A Systematic Review

A Novel Predictive Machine Learning Model Integrating Cytokines in Cervical-Vaginal Mucus Increases the Prediction Rate for Preterm Birth

Preterm birth (PB) is a leading cause of perinatal morbidity and mortality. PB prediction is performed by measuring cervical length, with a detection rate of around 70%. Although it is known that a cytokine-mediated inflammatory process is involved in the pathophysiology of PB, none screening method implemented in clinical practice includes cytokine levels as a predictor variable. Here, we quantified cytokines in cervical-vaginal mucus of pregnant women (18-23.6 weeks of gestation) with high or low risk for PB determined by cervical length, also collecting relevant obstetric information. IL-2, IL-6, IFN-γ, IL-4, and IL-10 were significantly higher in the high-risk group, while IL-1ra was lower. Two different models for PB prediction were created using the Random Forest machine-learning algorithm: a full model with 12 clinical variables and cytokine values and the adjusted model, including the most relevant variables-maternal age, IL-2, and cervical length- (detection rate 66 vs. 87%, false positive rate 12 vs. 3.33%, false negative rate 28 vs. 6.66%, and area under the curve 0.722 vs. 0.875, respectively). The adjusted model that incorporate cytokines showed a detection rate eight points higher than the gold standard calculator, which may allow us to identify the risk PB risk more accurately and implement strategies for preventive interventions.

Comparison of oral Dydrogesterone and 17-α hydroxyprogesterone caprate in the prevention of preterm birth

Background

Preterm birth (PTB) remains a significant problem in obstetric care. Progesterone supplements are believed to reduce the rate of preterm labor, but formulation, type of administration, and dosage varies in different studies. This study was performed to compare oral Dydrogesterone with intramuscular 17α-hydroxyprogesterone caproate (17α-OHPC) administration in prevention of PTB.

Methods

In this randomized clinical trial, we studied 150 women with singleton pregnancy in 28^Th-34^Th Gestational week, who had received tocolytic treatment for preterm labor. Participants were divided to receive 30 mg oral Dydrogesterone daily, 250 mg intramuscular 17α-OHPC weekly, or no intervention (control group). All treatments were continued until 37^Th Week or delivery, whichever occurred earlier. Obstetric outcomes, including latency period, gestational age at delivery, birth weight, neonatal intensive care unit (NICU) admission, and neonatal mortality were recorded. All patients were monitored biweekly until delivery.

Results

Baseline gestational age was not significantly different between groups. Latency period was significantly longer in the progesterone group compared with Dydrogesterone and control groups (41.06 ± 17.29 vs. 29.44 ± 15.6 and 22.20 ± 4.51 days, respectively; P < 0.001). The progesterone group showed significantly better results compared with the other two groups, in terms of gestational age at delivery, birth weight, and Apgar score (P < 0.001). None of the participants showed severe complications, stillbirth, or gestational diabetes.

Conclusion

Progesterone caproate can strongly prolong the latency period and improve neonatal outcomes and therefore, is superior to oral Dydrogesterone in the prevention of PTB.

Prevention of Preterm Birth with Progesterone

Gestational age at birth is a critical factor for perinatal and adulthood outcomes, and even for transgenerational conditions' effects. Preterm birth (PTB) (prematurity) is still the main determinant for infant mortality and morbidity leading cause of infant morbidity and mortality. Unfortunately, preterm birth (PTB) is a relevant public health issue worldwide and the global PTB rate is around 11%. The premature activation of labor is underlined by complex mechanisms, with a multifactorial origin influenced by numerous known and probably unknown triggers. The possible mechanisms involved in a too early labor activation have been partially explained, and involve chemokines, receptors, and imbalanced inflammatory paths. Strategies for the early detection and prevention of this obstetric condition were proposed in clinical settings with interesting results. Progesterone has been demonstrated to have a key role in PTB prevention, showing several positive effects, such as lower prostaglandin synthesis, the inhibition of cervical stromal degradation, modulating the inflammatory response, reducing gap junction formation, and decreasing myometrial activation. The available scientific knowledge, data and recommendations address multiple current areas of debate regarding the use of progesterone in multifetal gestation, including different formulations, doses and routes of administration and its safety profile in pregnancy.

Vaginal progesterone for prevention of preterm birth in asymptomatic high-risk women with a normal cervical length: a systematic review and meta-analysis protocol

BACKGROUND

Preterm birth (PTB) is estimated to affect 14.9 million babies globally every year. Global rates of PTB continue to increase from 9.8 to 10.6% over a 15-year period from 2000 to 2014. Vaginal progesterone is commonly used by clinicians as a prevention strategy, with recent evidence affirming the benefit of vaginal (micronised) progesterone to prevent PTB in women with a shortened cervix (< 25 mm). Given the low incidence of a short cervix at mid-gestation in high-risk populations further evidence is required. The objective of this review is to determine if vaginal progesterone reduces spontaneous preterm birth (sPTB) before 37 weeks in asymptomatic high-risk women with a singleton pregnancy with a normal mid-gestation cervical length.

METHODS

Studies will be sourced from MEDLINE, Embase and Cochrane Register of Trials (CENTRAL) from their inception onwards with the search terms 'progesterone' and 'preterm birth'. Studies will be screened and included if they assess vaginal progesterone compared to placebo in women with a normal cervical length. The primary outcome will be sPTB < 37 weeks, with secondary outcomes of sPTB < 34 weeks. Two independent reviewers will conduct study screening at abstract and full text level, data extraction and risk of bias assessment with disagreements resolved by an experienced researcher. The Mantel-Haenszel statistical method and random effects analysis model will be used to produce treatment effect odds ratios and corresponding 95% confidence intervals.

DISCUSSION

This review will assess the current body of evidence and provide clarity regarding the potential benefits and best practice of use of vaginal progesterone in asymptomatic women with high-risk singleton pregnancies and normal cervical length.

TRIAL REGISTRATION

PROSPERO CRD42020152051.

Prenatal Nutritional Strategies to Reduce the Risk of Preterm Birth

Worldwide, around 15 million preterm babies are born annually, and despite intensive research, the specific mechanisms triggering preterm birth (PTB) remain unclear. Cost-effective primary prevention strategies to reduce PTB are required, and nutritional interventions offer a promising alternative. Nutrients contribute to a variety of mechanisms that are potentially important to preterm delivery, such as infection, inflammation, oxidative stress, and muscle contractility. Several observational studies have explored the association between dietary nutrients and/or dietary patterns and PTB, often with contrasting results. Randomized trial evidence on the effects of supplementation with zinc, multiple micronutrients (iron and folic acid), and vitamin D is promising; however, results are inconsistent, and many studies are not adequately powered for outcomes of PTB. Large-scale clinical trials with PTB as the primary outcome are needed before any firm conclusions can be drawn for these nutrients. The strongest evidence to date for a nutritional solution exists for omega-3 long-chain polyunsaturated fatty acids (LCPUFAs), key nutrients in fish. In 2018, a Cochrane Review (including 70 studies) showed that prenatal supplementation with omega-3 LCPUFAs reduced the risk of PTB and early PTB (EPTB) compared with no omega-3 supplementation. However, the largest trial of omega-3 supplementation in pregnancy, the Omega-3 to Reduce the Incidence of Prematurity (ORIP) trial (n = 5,544), showed no reduction in EPTB and a reduction in PTB only in a prespecified analysis of singleton pregnancies. Exploratory analyses from the ORIP trial found that women with low baseline total omega-3 status were at higher risk of EPTB, and that this risk was substantially reduced with omega-3 supplementation. In contrast, women with replete or high baseline total omega-3 status were already at low risk of EPTB and additional omega-3 supplementation increased the risk of EPTB compared to control. These findings suggest that determining an individual woman's PUFA status may be the most precise way to inform recommendations to reduce her risk of PTB.

Novel pathways of inflammation in human fetal membranes associated with preterm birth and preterm pre-labor rupture of the membranes

Spontaneous preterm birth (PTB) and preterm pre-labor rupture of the membranes (pPROM) are major pregnancy complications. Although PTB and pPROM have common etiologies, they arise from distinct pathophysiologic pathways. Inflammation is a common underlying mechanism in both conditions. Balanced inflammation is required for fetoplacental growth; however, overwhelming inflammation (physiologic at term and pathologic at preterm) can lead to term and preterm parturition. A lack of effective strategies to control inflammation and reduce the risk of PTB and pPROM suggests that there are several modes of the generation of inflammation which may be dependent on the type of uterine tissue. The avascular fetal membrane (amniochorion), which provides structure, support, and protection to the intrauterine cavity, is one of the key contributors of inflammation. Localized membrane inflammation helps tissue remodeling during pregnancy. Two unique mechanisms that generate balanced inflammation are the progressive development of senescence (aging) and cyclic cellular transitions: epithelial to mesenchymal (EMT) and mesenchymal to epithelial (MET). The intrauterine build-up of oxidative stress at term or in response to risk factors (preterm) can accelerate senescence and promote a terminal state of EMT, resulting in the accumulation of inflammation. Inflammation degrades the matrix and destabilizes membrane function. Inflammatory mediators from damaged membranes are propagated via extracellular vesicles (EV) to maternal uterine tissues and transition quiescent maternal uterine tissues into an active state of labor. Membrane inflammation and its propagation are fetal signals that may promote parturition. This review summarizes the mechanisms of fetal membrane cellular senescence, transitions, and the generation of inflammation that contributes to term and preterm parturitions.

Copolymer Composition and Nanoparticle Configuration Enhance in vitro Drug Release Behavior of Poorly Water-soluble Progesterone for Oral Formulations

HYPOTHESIS

Developing oral formulations to enable effective release of poorly water-soluble drugs like progesterone is a major challenge in pharmaceutics. Coaxial electrospray can generate drug-loaded nanoparticles of strategic compositions and configurations to enhance physiological dissolution and bioavailability of poorly water-soluble drug progesterone.

EXPERIMENTS

Six formulations comprising nanoparticles encapsulating progesterone in different poly(lactide-co-glycolide) (PLGA) matrix configurations and compositions were fabricated and characterized in terms of morphology, molecular crystallinity, drug encapsulation efficiency and release behavior.

FINDINGS

A protocol of fabrication conditions to achieve 100% drug encapsulation efficiency in nanoparticles was developed. Scanning electron microscopy shows smooth and spherical morphology of 472.1±54.8 to 588.0±92.1 nm in diameter. Multiphoton Airyscan super-resolution confocal microscopy revealed core-shell nanoparticle configuration. Fourier transform infrared spectroscopy confirmed presence of PLGA and progesterone in all formulations. Diffractometry indicated amorphous state of the encapsulated drug. UV-vis spectroscopy showed drug release increased with hydrophilic copolymer glycolide ratio while core-shell formulations with progesterone co-dissolved in PLGA core exhibited enhanced release over five hours at 79.9±1.4% and 70.7±3.5% for LA:GA 50:50 and 75:25 in comparison with pure progesterone without polymer matrix in the core at 67.0±1.7% and 57.5±2.8%, respectively. Computational modeling showed good agreement with the experimental drug release behavior in vitro.

Vaginal compared with intramuscular progestogen for preventing preterm birth in high-risk pregnant women (VICTORIA study): a multicentre, open-label randomised trial and meta-analysis

OBJECTIVE

To compare the efficacy of two types of progestogen therapy for preventing preterm birth (PTB) and to review the relevant literature.

DESIGN

A multicentre, randomised, open-label, equivalence trial and a meta-analysis.

SETTING

Tertiary referral hospitals in South Korea.

POPULATION

Pregnant women with a history of spontaneous PTB or short cervical length (<25 mm).

METHODS

Eligible women were screened and randomised at 16-22 weeks of gestation to receive either 200 mg of vaginal micronised progesterone daily (vaginal group) or an intramuscular injection of 250 mg 17α-hydroxyprogesterone caproate weekly (IM group). Stratified randomisation was carried out according to participating centres and indications for progestogen therapy. This trial was registered at ClinicalTrials.gov (NCT02304237).

MAIN OUTCOME MEASURE

Preterm birth (PTB) before 37 weeks of gestation.

RESULTS

A total of 266 women were randomly assigned and a total of 247 women (119 and 128 women in the vaginal and IM groups, respectively) were available for the intention-to-treat analysis. Risks of PTB before 37 weeks of gestation did not significantly differ between the two groups (22.7 versus 25.8%, P = 0.571). The difference in PTB risk between the two groups was 3.1% (95% CI -7.6 to 13.8%), which was within the equivalence margin of 15%. The meta-analysis results showed no significant differences in the risk of PTB between the vaginal and IM progestogen treatments.

CONCLUSION

Compared with vaginal progesterone, treatment with intramuscular progestin might increase the risk of PTB before 37 weeks of gestation by as much as 13.8%, or reduce the risk by as much as 7.6%, in women with a history of spontaneous PTB or with short cervical length.

TWEETABLE ABSTRACT

Vaginal and intramuscular progestogen showed equivalent efficacy for preventing preterm birth before 37 weeks of gestation.

The use of progesterone during pregnancy to prevent preterm birth

One of the most significant problems facing maternal and children health worldwide is preterm birth (PTB). Although strategies to increase the survival of premature infants have significantly improved in the past few decades, they have yet to be successful. Nine years ago, the use of progesterone in pregnancy was approved by the United States Food and Drug Administration (FDA) for PTB prevention. This paper reviews the recent evidence supporting the use of progesterone in pregnancy for PTB prevention and provides guidelines for its use in daily clinical practice. The guidelines address multiple current controversial areas regarding the prevention of PTB to aid physicians with their clinical decision-making practice, including the use in multifetal gestation, different formulations, safety in pregnancy, dose and route of administration.Saudi Med J 2020; Vol. 41 (4): 333-340doi: 10.15537/smj.2020.4.25036How to cite this article:Alsulmi ES, Alfaraj M, Faden Y, Al Qahtani N. The use of progesterone during pregnancy to prevent preterm birth. Saudi Med J 2020; Vol. 41: 333-340. doi: 10.15537/smj.2020.4.25036.

Infertility treatments during pregnancy and the risk of autism spectrum disorder in the offspring

We aimed to examine the effects of infertility treatments on the risk of Autism Spectrum Disorder (ASD). Data were from a representative national registry on 110,093 male live births in Israel (born: 1999-2008; and ASD: 975, 0.9%). Infertility treatments included In Vitro Fertilization (IVF), and five hormone treatments. Relative risk (RR) was estimated with multivariable logistic models. Results showed that IVF treatment compared with spontaneous conception was not statistically significantly associated with the risk of ASD. Only progesterone hormone treatment was associated with a statistically significant (p < .05) increased risk of ASD (RR = 1.51, 95% CI 1.22, 1.86) compared to the group with no progesterone treatment. In conclusion, progesterone exposure during the critical period of fetal life elevated the risk of ASD, possibly reflecting epigenetic modification.

The development of progesterone-loaded nanofibers using pressurized gyration: A novel approach to vaginal delivery for the prevention of pre-term birth

Recent evidence has continued to support the applicability of progesterone in preventing preterm birth, hence the development of an appropriate vaginal delivery system for this drug would be of considerable interest. Here, we describe the development of progesterone-loaded bioadhesive nanofibers using pressurized gyration for potential incorporation into a vaginal insert, with a particular view to addressing the challenges of incorporating a poorly water-soluble drug into a hydrophilic nanofiber carrier. Polyethylene oxide and carboxymethyl cellulose were chosen as polymers to develop the carrier systems, based on previous evidence of their yielding mucoadhesive nanofibers using the pressurized gyration technique. The fabrication parameters such as solvent system, initial drug loading and polymer composition were varied to facilitate optimisation of fiber structure and efficiency of drug incorporation. Such studies resulted in the formation of nanofibers with satisfactory surface appearance, diameters in the region of 400 nm and loading of up to 25% progesterone. Thermal and spectroscopic analyses indicated that the drug was incorporated in a nanocrystalline state. Release from the drug-loaded fibers indicated comparable rates of progesterone dissolution to that of Cyclogest, a commercially available progesterone pessary, allowing release over a period of hours. Overall, the study has shown that pressurized gyration may produce bioadhesive progesterone-loaded nanofibers which have satisfactory loading of a poorly water-soluble drug as well as having suitable structural and release properties. The technique is also capable of producing fibers at a yield commensurate with practical applicability, hence we believe that the approach shows considerable promise for the development of progesterone dosage forms for vaginal application.

Delayed second twin delivery: benefits and risks

BACKGROUND

An increasing number of reports describe the delayed second twin delivery for days, or weeks with good results in the majority of the cases, and different survival rate between centers, without reported randomized controlled trials (RCTs).

OBJECTIVES

This study was designed to evaluate the suggested management of the delayed second twin delivery in the Sabah Maternity Hospital regarding its outcome, possible risks, and benefits.

PATIENTS AND METHODS

Forty-seven twin pregnancies with preterm labor (PTL) of the first fetus between 20-30 weeks, and delayed delivery of the second twin were included in this study. Studied women signed informed consent about the possible risks of keeping the live fetus in the hostile intrauterine environment, and benefits of the prolonged gestation for the second twin. Throughout the conservative treatment of the second twin, the studied women were hospitalized with regular follow up for infections, consumptive coagulopathy parameters, and wellbeing of the second twin.

RESULTS

There was significant difference in the gestational age at delivery between the first and second twin (22.6 ± 3.4 versus 34.3 ± 2.5 weeks; respectively, p = .01). There was significant difference in the birth weight between the first and second twin (435 ± 91.2 versus 1472 ± 61.5 g; respectively, p = .004). The rate of the cesarean delivery was significantly high during delivery of the second twin compared with the first twin (23.4% (11/47) versus 0% (0/47); respectively, p = .0001) with high survival rate for the second twin (85.1% (40/47)) after the delayed second twin delivery.

CONCLUSIONS

The birth weight, the gestational age, and the survival rate of the studied second twin significantly increased after the suggested management of the delayed second twin delivery.

Is progestogen supplementation necessary to prevent abortion?

A prospective study was conducted to evaluate the effect of progestogens on the pregnancy outcome of threatened abortion (TA). A total of 251 pregnant women less than 20 weeks of gestational age (GA) were included. Group 1 consisted of women with vaginal bleeding who had already been under treatment with progestogens and Group 2 was composed of women with vaginal bleeding who were only followed without progestogen therapy, whereas Group 3 was the control group without any vaginal bleeding or progestogen therapy. The pregnancy outcomes and serum progesterone levels were compared among the groups. The mean serum progesterone concentrations were statistically significantly higher in Group 1 in comparison to Group 2 and 3 (p < 0.001). Abortion rates were similar among the study groups. Although progestogen supplementation leads to increased level of serum progesterone, this finding does not translate to its beneficial effect on the pregnancy outcomes in cases of TAs.

Does progesterone administration in preterm labor influence Treg cells?

OBJECTIVES

The aim of this study was to determine if the actions of progesterone on preterm labor are accomplished through modulation of the percentage of regulatory T-cells (Treg).

METHODS

The study was a cohort pilot study made in a single center tertiary obstetrical unit with women in preterm labor arrested with tocolytic treatment. Variation of the number and percentage of Treg cells obtained from peripheral blood samples of women with preterm labor were calculated by flow cytometry, before and after progesterone administration.

RESULTS

In the paired samples for each patient, there was a significant difference in the Treg cell pool after progesterone treatment, with an increase in both their percentage (48.9 vs. 53; P=0.07) and absolute number (14.8 vs. 56.5 cells/μL; P=0.046).

CONCLUSIONS

This research demonstrated a considerable increase in the Treg cell pool after progesterone treatment. This indicates a possible mechanism for progesterone treatment benefits in preterm labor, potentially increasing its more rational use.

Obstetric care after radical abdominal trachelectomy in a patient with stage IB1 cervical cancer: A case report and a review of medical literature

•A case on obstetric care after radical trachelectomy in early cervical cancer•Fertility sparing surgery provides favorable oncological and obstetrical outcomes.•Multidisciplinary teams are essential in managing this patient population.

Vaginal progesterone prophylaxis for preterm birth (the OPPTIMUM study): a multicentre, randomised, double-blind trial

BACKGROUND

Progesterone administration has been shown to reduce the risk of preterm birth and neonatal morbidity in women at high risk, but there is uncertainty about longer term effects on the child.

METHODS

We did a double-blind, randomised, placebo-controlled trial of vaginal progesterone, 200 mg daily taken from 22-24 to 34 weeks of gestation, on pregnancy and infant outcomes in women at risk of preterm birth (because of previous spontaneous birth at ≤34 weeks and 0 days of gestation, or a cervical length ≤25 mm, or because of a positive fetal fibronectin test combined with other clinical risk factors for preterm birth [any one of a history in a previous pregnancy of preterm birth, second trimester loss, preterm premature fetal membrane rupture, or a history of a cervical procedure to treat abnormal smears]). The objective of the study was to determine whether vaginal progesterone prophylaxis given to reduce the risk of preterm birth affects neonatal and childhood outcomes. We defined three primary outcomes: fetal death or birth before 34 weeks and 0 days gestation (obstetric), a composite of death, brain injury, or bronchopulmonary dysplasia (neonatal), and a standardised cognitive score at 2 years of age (childhood), imputing values for deaths. Randomisation was done through a web portal, with participants, investigators, and others involved in giving the intervention, assessing outcomes, or analysing data masked to treatment allocation until the end of the study. Analysis was by intention to treat. This trial is registered at ISRCTN.com, number ISRCTN14568373.

FINDINGS

Between Feb 2, 2009, and April 12, 2013, we randomly assigned 1228 women to the placebo group (n=610) and the progesterone group (n=618). In the placebo group, data from 597, 587, and 439 women or babies were available for analysis of obstetric, neonatal, and childhood outcomes, respectively; in the progesterone group the corresponding numbers were 600, 589, and 430. After correction for multiple outcomes, progesterone had no significant effect on the primary obstetric outcome (odds ratio adjusted for multiple comparisons [OR] 0·86, 95% CI 0·61-1·22) or neonatal outcome (OR 0·62, 0·38-1·03), nor on the childhood outcome (cognitive score, progesterone group vs placebo group, 97·3 [SD 17·9] vs 97·7 [17·5]; difference in means -0·48, 95% CI -2·77 to 1·81). Maternal or child serious adverse events were reported in 70 (11%) of 610 patients in the placebo group and 59 (10%) of 616 patients in the progesterone group (p=0·27).

INTERPRETATION

Vaginal progesterone was not associated with reduced risk of preterm birth or composite neonatal adverse outcomes, and had no long-term benefit or harm on outcomes in children at 2 years of age.

FUNDING

Efficacy and Mechanism Evaluation (EME) Programme, a Medical Research Council (MRC) and National Institute for Health Research (NIHR) partnership. The EME Programme is funded by the MRC and NIHR, with contributions from the Chief Scientist Office in Scotland and National Institute for Social Care and Research in Wales.

Sulfasalazine augments a pro-inflammatory response in interleukin-1β-stimulated amniocytes and myocytes

Preterm birth occurs in 10% of pregnancies and is a major cause of neonatal morbidity and mortality. The majority of cases of early preterm labour are associated with infection/inflammation, which places the fetal central nervous system at risk. Targeting immune activation is therefore an appealing therapeutic strategy for the prevention of preterm labour and neonatal brain injury. The expression of many labour-associated and inflammatory-response genes is controlled by the transcription factors nuclear factor-κB (NF-κB) and activator protein-1 (AP-1), which makes them therapeutic targets of interest. Sulfasalazine (SASP) has been shown to inhibit NF-κB and reduce lipopolysaccharide-induced cytokine concentrations in fetal membrane explants and reduce the rate of Escherichia coli-induced preterm labour in mice. Its effects upon AP-1 in the context of pregnancy are unknown. In this study the effect of SASP on interleukin-1β (IL-1β) -induced NF-κB and AP-1 activity, cytokine production and cyclo-oxygenase-2 (COX-2) expression was examined in amniocytes and myocytes. A supra-therapeutic concentration (5 mm) was required to inhibit IL-1β-induced NF-κB (P < 0·0001) in amniocytes and IL-1β-induced NF-κB (P < 0·01), AP-1 (P < 0·01) and COX-2 (P < 0·05) in myocytes. Despite inhibiting IL-1β-induced cytokines, a basal increase in IL-6 (P < 0·01), IL-8 (P < 0·0001) and tumour necrosis factor-α (TNF-α) (P < 0·001) was seen with 5 mm SASP in amniocytes, and significant cytotoxic effects were seen in myocytes. The therapeutic concentration of 0·015 mm had no inhibitory effects on pro-inflammatory mediators, but led to an augmented response to IL-1β-induced IL-6 (P < 0·01), IL-8 (P < 0·05) and TNF-α (P < 0·05) in amniocytes and IL-8 (P < 0·05) in myocytes. SASP is therefore an unlikely therapeutic candidate for the prevention of inflammation-induced preterm labour.

Comparative Study of Vaginal versus Intramuscular Progesterone in the Prevention of Preterm Delivery: A Randomized Clinical Trial

BACKGROUND

Preterm birth is a worldwide health concern due to its various negative consequences. Therefore, the prevention of preterm birth is a top priority for healthcare systems in all countries.

OBJECTIVE

To compare the effectiveness of vaginal versus intramuscular progesterone in the prevention of preterm delivery.

METHODS

This randomized clinical trial was conducted at Shahid Sadoughi Hospital in Yazd, Iran, from November 21, 2012 to January 20, 2015. Seventy-eight pregnant women with singleton pregnancy and one risk factor of preterm delivery were included in the study. The subjects were assigned randomly to two groups, with group one receiving Cyclogest and group two receiving 17-α hydroxyprogesterone caproate. Subsequently, we analyzed drug complications during pregnancy, delivery time, neonatal outcomes, and patients' satisfaction among the two groups. The data were analyzed using SPSS version 16. We used descriptive statistics, chi-squared, t-test, and ANOVA for the analyses of primary and secondary outcomes.

RESULTS

Among the 39 births in group one, 33.3% occurred preterm, and, among the 39 births in group two, 30.7% occurred preterm (< 37 weeks). The mean gestational ages at delivery in groups 1 and 2 were 37.07 ± 2.23 and 36.81 ± 2.77 weeks, respectively (p = 0.765). Other variables were not significantly different between the two groups, including birth weight (p = 0.745), Apgar scores for the first and fifth minutes (p = 0.574, 0.630), length of stay in the neonatal intensive care unit (NICU) when the newborns needed hospitalization (p = 0.358), and the patients' satisfaction with the drugs that were used (p = 0.615).

CONCLUSIONS

In this study, vaginal progesterone and intramuscular progesterone had the same levels of effectiveness, safety and acceptance by patients in the prevention of preterm delivery. Therefore, both can be used for this purpose in clinical practices, but more studies are needed.

Evaluation of two treatment strategies for the prevention of preterm birth in women identified as at risk by ultrasound (PESAPRO Trial): study protocol for a randomized controlled trial

Background

Premature birth is considered one of the main problems in modern Obstetrics. It causes more than 50 % of neonatal mortality; it is responsible for a large proportion of infant morbidity and incurs very high economic costs. Cervical length, which can be accurately measured by ultrasound, has an inverse relationship with the risk of preterm birth. As a result, having an effective intervention for asymptomatic patients with short cervix could reduce the prematurity. Although recently published data demonstrates the effectiveness of vaginal progesterone and cervical pessary, these treatments have never been compared to one another.

Methods/Design

The PESAPRO study is a noncommercial, multicenter, open-label, randomized clinical trial (RCT) in pregnant women with a short cervix as identified by transvaginal ultrasonography at 19 to 22 weeks of gestation. Patients are randomized (1:1) to either daily vaginal progesterone or cervical pessary until the 37th week of gestation or delivery; whichever comes first. During the trial, women visit every 4 weeks for routine questions and tests. The primary outcome is the proportion of spontaneous preterm deliveries before 34 weeks of gestation. A sample size of 254 pregnant women will be included at 29 participating hospitals in order to demonstrate noninferiority of placing a pessary versus vaginal progesterone. The first patient was randomized in August 2012, and recruitment of study subjects will continue until the end of December 2015.

Discussion

This trial assesses the comparative efficacy and safety between two accepted treatments, cervical pessary versus vaginal progesterone, and it will provide evidence in order to establish clinical recommendations.

Trial registration

EU Clinical Trials Register EudraCT2012-000241-13 (Date of registration: 16 January 2012); ClinicalTrials.gov Identifier NCT01643980 (Date of registration: 12 June 2012).

Use and attitudes of obstetricians toward 3 high-risk interventions in MFMU Network hospitals

OBJECTIVE

We sought to evaluate the frequency of, and factors associated with, the use of 3 evidence-based interventions: antenatal corticosteroids for fetal lung maturity, progesterone for prevention of recurrent preterm birth, and magnesium sulfate for fetal neuroprotection.

STUDY DESIGN

A self-administered survey was conducted from January through May 2011 among obstetricians from 21 hospitals that included 30 questions regarding their knowledge, attitudes, and practice of the 3 evidence-based interventions and the 14-item short version of the Team Climate for Innovation survey. Frequency of use of each intervention was ascertained from an obstetrical cohort of women between January 2010 and February 2011.

RESULTS

A total of 329 obstetricians (74% response rate) who managed 16,946 deliveries within the obstetrical cohort participated in the survey. More than 90% of obstetricians reported that they incorporated each intervention into routine practice. Actual frequency of administration in women eligible for the treatments was 93% for corticosteroids, 39% for progesterone, and 71% for magnesium sulfate. Provider satisfaction with quality of treatment evidence was 97% for corticosteroids, 82% for progesterone, and 57% for magnesium sulfate. Obstetricians perceived that barriers to treatment were most frequent for progesterone (76%), 30% for magnesium sulfate, and 17% for corticosteroids. Progesterone use was more frequent among patients whose provider reported the quality of the evidence was above average to excellent compared with poor to average (42% vs 25%, respectively; P < .001), and they were satisfied with their knowledge of the intervention (41% vs 28%; P = .02), and was less common among patients whose provider reported barriers to hospital or pharmacy drug delivery (31% vs 42%; P = .01). Corticosteroid administration was more common among patients who delivered at hospitals with 24 hours a day-7 days a week maternal-fetal medicine specialist coverage (93% vs 84%; P = .046), CONCLUSION: Obstetricians in Maternal-Fetal Medicine Units Network hospitals frequently use these evidence-based interventions; however, progesterone use was found to be related to their assessment of evidence quality. Neither progesterone nor the other interventions were associated with overall climate of innovation within a hospital as measured by the Team Climate for Innovation. National Institutes of Health Consensus Conference Statements may also have an impact on use; there is such a statement for antenatal corticosteroids but not for progesterone for preterm prevention or magnesium sulfate for fetal neuroprotection.

STOPPIT Baby Follow-up Study: the effect of prophylactic progesterone in twin pregnancy on childhood outcome

OBJECTIVES

To determine the long-term effects of in utero progesterone exposure in twin children.

METHODS

This study evaluated the health and developmental outcomes of all surviving children born to mothers who participated in a double-blind, placebo-controlled trial of progesterone given for the prevention of preterm birth in twin pregnancies (STOPPIT, ISRCTN35782581). Follow-up was performed via record linkage and two parent-completed validated questionnaires, the Child Development Inventory and the Health Utilities Index.

RESULTS

Record linkage was successfully performed on at least one record in 759/781 (97%) children eligible for follow-up. There were no differences between progesterone-exposed and placebo-exposed twins with respect to incidence of death, congenital anomalies and hospitalisation, nor on routine national child health assessments. Questionnaire responses were received for 324/738 (44%) children. The mean age at questionnaire follow-up was 55.5 months. Delay in at least one developmental domain on the Child Development Inventory was observed in 107/324 (33%) children, with no evidence of difference between progesterone-exposed and placebo-exposed twins. There was no evidence of difference between the progesterone and placebo groups in global health status assessed using the Health Utilities Index: 89% of children were rated as having 'excellent' health and a further 8% as having 'very good' health.

CONCLUSIONS

In this cohort of twin children there was no evidence of a detrimental or beneficial impact on health and developmental outcomes at three to six years of age due to in utero exposure to progesterone.

Oxidative stress damage as a detrimental factor in preterm birth pathology

Normal term and spontaneous preterm births (PTB) are documented to be associated with oxidative stress (OS), and imbalances in the redox system (balance between pro- and antioxidant) have been reported in the maternal-fetal intrauterine compartments. The exact mechanism of labor initiation either at term or preterm by OS is still unclear, and this lack of understanding can partially be blamed for failure of antioxidant supplementation trials in PTB prevention. Based on recent findings from our laboratory, we postulate heterogeneity in host OS response. The physiologic (at term) and pathophysiologic (preterm) pathways of labor are not mediated by OS alone but by OS-induced damage to intrauterine tissues, especially fetal membranes of the placenta. OS damage affects all major cellular elements in the fetal cells, and this damage promotes fetal cell senescence (aging). The aging of the fetal cells is predominated by p38 mitogen activated kinase (p38MAPK) pathways. Senescing cells generate biomolecular signals that are uterotonic, triggering labor process. The aging of fetal cells is normal at term. However, aging is premature in PTB, especially in those PTBs complicated by preterm premature rupture of the membranes, where elements of redox imbalances and OS damage are more dominant. We postulate that fetal cell senescence signals generated by OS damage are likely triggers for labor. This review highlights the mechanisms involved in senescence development at term and preterm by OS damage and provides insight into novel fetal signals of labor initiation pathways.

Folic acid supplementation, dietary folate intake during pregnancy and risk for spontaneous preterm delivery: a prospective observational cohort study

BACKGROUND

Health authorities in numerous countries recommend periconceptional folic acid supplementation to prevent neural tube defects. The objective of this study was to examine the association of dietary folate intake and folic acid supplementation during different periods of pregnancy with the risk of spontaneous preterm delivery (PTD).

METHODS

The Norwegian Mother and Child Cohort Study is a population-based prospective cohort study. A total of 66,014 women with singleton pregnancies resulting in live births in 2002-2009 were included. Folic acid supplementation was self-reported from 26 weeks before pregnancy until pregnancy week 24. At gestational week 22, the women completed a food frequency questionnaire, which allowed the calculation of their average total folate intake from foods and supplements for the first 4-5 months of pregnancy. Spontaneous PTD was defined as the spontaneous onset of delivery between weeks 22+0 and 36+6 (n = 1,755).

RESULTS

The median total folate intake was 313 μg/d (interquartile range IQR 167-558) in the overall population and 530 μg/d (IQR 355-636) in the supplement users. Eighty-five percent reported any folic acid supplementation from <8 weeks before to 24 weeks after conception while only 44% initiated folic acid supplementation before pregnancy. Cox regression analysis showed that the amount of dietary folate intake (hazard ratio HR 1.00; confidence interval 95% CI 0.61-1.65) and supplemental folate intake (HR 1.00; CI 1.00-1.00) was not significantly associated with the risk of PTD. The initiation of folic acid supplementation more than 8 weeks before conception was associated with an increased risk for spontaneous PTD (HR 1.18; CI 1.05-1.32) compared to no folic acid supplementation preconception. There was no significant association with PTD when supplementation was initiated within 8 weeks preconception (HR 0.99; CI 0.87-1.13). All analyses were adjusted for maternal characteristics and socioeconomic, health and dietary variables.

CONCLUSIONS

Our findings do not support a protective effect of dietary folate intake or folic acid supplementation on spontaneous PTD. Preconceptional folic acid supplementation starting more than 8 weeks before conception was associated with an increased risk of spontaneous PTD. These results require further investigation before discussing an expansion of folic acid supplementation guidelines.

A randomised controlled double-blind clinical trial of 17-hydroxyprogesterone caproate for the prevention of preterm birth in twin gestation (PROGESTWIN): evidence for reduced neonatal morbidity

OBJECTIVE

To determine whether 17 alpha-hydroxyprogesterone caproate (17OHPC) prolongs gestation beyond 37 weeks of gestation (primary outcome) and reduces neonatal morbidity (secondary outcome) in twin pregnancy.

DESIGN

Randomised controlled double-blind clinical trial.

SETTING

Tertiary-care university medical centre.

POPULATION

Unselected women with twin pregnancies.

METHODS

Participants received weekly injections of 250 mg 17OHPC (n = 194) or placebo (n = 94), from 16-20 to 36 weeks of gestation. Randomisation was performed using the permuted-block randomisation method. Data were analysed on an intention-to-treat basis.

MAIN OUTCOME MEASURE

Preterm birth (PTB) rate before 37 weeks of gestation.

RESULTS

There were no significant differences in the average gestational age at delivery, or in the rates of PTB before 37, 32, and 28 weeks of gestation, between the two groups. The proportion of very-low-birthweight neonates (<1500 g) was significantly lower in the 17OHPC group (7.6%) compared with placebo (14.3%) (relative risk, RR 0.5; 95% confidence interval, 95% CI 0.3-0.9; P = 0.01). Progestogen-treated neonates had a significantly lower composite neonatal morbidity (19.1%) compared with placebo (30.9%) (odds ratio, OR 0.53; 95% CI 0.31-0.90; P = 0.02), with significantly lower odds for respiratory distress syndrome (14.4 versus 23.4%; OR 0.55; 95% CI 0.31-0.98; P = 0.04), retinopathy of prematurity (1.1 versus 4.6%; OR 0.21; 95% CI 0.05-0.96; P = 0.04), and culture-confirmed sepsis (3.4 versus 12.8%; OR 0.24; 95% CI 0.10-0.57; P = 0.00).

CONCLUSIONS

Intramuscular 17OHPC therapy did not reduce PTB before 37 weeks of gestation in unselected twin pregnancies. Nonetheless, 17OHPC significantly reduced neonatal morbidity parameters and increased birthweight.

Progesterone induces apoptosis of insulin-secreting cells: insights into the molecular mechanism

Progesterone has been associated with the development of gestational diabetes (GD) due to the enhancement of insulin resistance. As β-cell apoptosis participates in type 1 and type 2 diabetes pathophysiology, we proposed the hypothesis that progesterone might contribute to the development of GD through a mechanism that also involves β-cell death. To address this question, RINm5F insulin-producing cells were incubated with progesterone (25-100 μM), in the presence or absence of α-tocopherol (40 μM). After 24 or 48 h, membrane integrity and DNA fragmentation were analyzed by flow cytometry. Caspase activity was used to identify the mode of cell death. The involvement of endoplasmic reticulum stress in the action of progesterone was investigated by western blotting. Oxidative stress was measured by 2',7'-dichlorofluorescein diacetate (DCFDA) oxidation. Isolated rat islets were used in similar experiments in order to confirm the effect of progesterone in primary β-cells. Incubation of RINm5F cells with progesterone increased the number of cells with loss of membrane integrity and DNA fragmentation. Progesterone induced generation of reactive species. Pre-incubation with α-tocopherol attenuated progesterone-induced apoptosis. Western blot analyses revealed increased expression of CREB2 and CHOP in progesterone-treated cells. Progesterone caused apoptotic death of rat islet cells and enhanced generation of reactive species. Our results show that progesterone can be toxic to pancreatic β-cells through an oxidative-stress-dependent mechanism that induces apoptosis. This effect may contribute to the development of GD during pregnancy, particularly under conditions that require administration of pharmacological doses of this hormone.

Progestational agents for treating threatened or established preterm labour

BACKGROUND

Prematurity is not only the leading cause of perinatal morbidity and mortality but is associated with long-term impairment. Studies of various tocolytic agents have shown mixed results with little effect in improving pregnancy duration and insufficient data to confirm a definite beneficial effect on neonatal morbidity or mortality. Progesterone is known to have an inhibitory effect on uterine contractility and is thought to play a key role in the maintenance of pregnancy until term.

OBJECTIVES

To determine if the use of progestational agents is effective as a form of treatment or co-treatment for women with threatened or established preterm labour with intact membranes.

SEARCH METHODS

We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (31 August 2013), CENTRAL (The Cochrane Library 2013, Issue 10), MEDLINE (1966 to August 31 2013) and Embase (1974 to 31 August 2013). We checked the reference lists of all included studies to identify any additional studies and communicated with authors and the pharmaceutical industry.

SELECTION CRITERIA

Randomised controlled trials that compared progestational agents, given either alone or in combination with other tocolytics, with a control group receiving another tocolytic, placebo or no treatment, for the treatment of preterm labour.

DATA COLLECTION AND ANALYSIS

Two review authors independently extracted data and assessed trial quality.

MAIN RESULTS

Eight studies were included in this review, involving 563 women, but only seven studies, involving 538 women, contributed data for analyses. There are some data suggesting that the use of progestational agents results in a reduction of preterm deliveries at less than 37 weeks of gestation and an increase in birthweight. The use of a progestational agent may also reduce the frequency of uterine contractions, prolong pregnancy and attenuate the shortening of cervical length. However, the analysis was limited by the relatively small number of available studies. The power of the meta-analysis was also limited by the varying types, dosages and routes of administration of progesterone.

AUTHORS' CONCLUSIONS

There is insufficient evidence to advocate progestational agents as a tocolytic for women presenting with preterm labour.

Regulation of progesterone signaling during pregnancy: implications for the use of progestins for the prevention of preterm birth

Preterm birth is a major cause of neonatal morbidity and mortality. Progesterone plays a critical role in suppressing the inflammatory signals that would induce parturition prior to term. Progesterone signaling is regulated in a variety of ways during pregnancy. Endocrine production of high levels of progesterone by the placenta ensures the availability of high levels of progesterone throughout pregnancy. Paracrine regulation of progesterone metabolism in target tissues, particularly the myometrium and cervix, also determines the amount of progesterone ligand available. Progesterone metabolism can also lead to the formation of metabolites that contribute to its effects. In particular, 5β-dihydroprogesterone formation by aldo-keto reductase 1D1 appears to play an important role in maintaining uterine quiescence. Progesterone signaling can also be regulated at the receptor level through changes in the relative expression of the nuclear progesterone receptor isoforms, reduced expression of membrane receptors, and changes in the expression levels of coactivators and/or corepressors, including nuclear factor κB. Progesterone and 17α-hydroxyprogesterone caproate (17OH-PC) have recently been shown to reduce preterm births in women with previous preterm birth or shortened cervix. It is important to realize that these two progestins are likely to act in significantly different ways, which will likely influence their efficacy. The structural differences and resistance to metabolism exhibited by 17OH-PC means that it will be unable to activate some of the pathways that progesterone activates, but that it also will not be subject to paracrine inactivation. The fact that progesterone therapy works for maintaining pregnancy in some women, indicates that for those women insufficient levels of progesterone ligand in target tissues is a determining factor in early parturition, despite high levels of circulating progesterone. This article is part of a Special Issue entitled 'Pregnancy and Steroids'.

Prevention of preterm delivery in twin pregnancy

The incidence of twin gestation has increased markedly over the past decades, mostly because of increased use of assisted reproductive technologies. Twin pregnancies are at increased risk of preterm delivery (i.e. birth before 37 weeks of gestation). Multiple gestations therefore account for 2-3% of all pregnancies but constitute at least 10% of cases of preterm delivery. Complications from preterm birth are not limited to the neonatal period, such as in retinopathy of prematurity, intraventricular haemorrhage, necrotising enterocolitis, respiratory disorder and sepsis; they can also constitute sequelae such as abnormal neurophysiological development in early childhood and underachievement in school. Several treatment modalities have been proposed in singleton high-risk pregnancies. The mechanism of initiating labour may, however, be different in singleton and twin gestations. Therefore, it is mandatory to evaluate the proposed treatments in randomised trials of multiple gestations. In this chapter, we describe the results of trials to prevent preterm delivery in twin pregnancies.

Folic acid supplementation, dietary folate intake during pregnancy and risk for spontaneous preterm delivery: a prospective observational cohort study

Background

Health authorities in numerous countries recommend periconceptional folic acid to pregnant women to prevent neural tube defects. The objective of this study was to examine the association of folic acid supplementation during different periods of pregnancy and of dietary folate intake with the risk of spontaneous preterm delivery (PTD).

Methods

The Norwegian Mother and Child Cohort Study is a population-based prospective cohort study. A total of 65,668 women with singleton pregnancies resulting in live births in 1999–2009 were included. Folic acid supplementation was self-reported from 26 weeks before pregnancy until week 24 during pregnancy. At gestational week 22, the women completed a food frequency questionnaire, which allowed the calculation of their average total folate intake from foods and supplements for the first 4–5 months of pregnancy. Spontaneous PTD was defined as the spontaneous onset of delivery between weeks 22⁺⁰ and 36⁺⁶ (n = 1,628).

Results

The median total folate intake was 266 μg/d (interquartile range IQR 154–543) in the overall population and 540 μg/d (IQR 369–651) in the supplement users. Eighty-three percent reported any folic acid supplementation from <8 weeks before to 24 weeks after conception while 42% initiated folic acid supplementation before their pregnancy. Cox regression analysis showed that the amount of folate intake from the diet (hazard ratio HR 1.16; confidence interval CI 0.65-2.08) and from the folic acid supplements (HR 1.04; CI 0.95-1.13) was not significantly associated with the risk of PTD. The initiation of folic acid supplementation more than 8 weeks before conception was associated with an increased risk for PTD (HR 1.19; CI 1.05-1.34) compared to no folic acid supplementation pre-conception. There was no significant association with PTD when supplementation was initiated within 8 weeks pre-conception (HR 1.01; CI 0.88-1.16). All analyses were adjusted for maternal characteristics and socioeconomic, health and dietary variables.

Conclusions

Our findings do not support a protective effect of dietary folate intake or folic acid supplementation on spontaneous PTD. Pre-conceptional folic acid supplementation starting more than 8 weeks before conception was associated with an increased risk of PTD. These results require further investigation before discussing an expansion of folic acid supplementation guidelines.

Comparison of cervical length in adult and adolescent nulliparae at mid-gestation

STUDY OBJECTIVE

To compare cervical lengths of adolescents and adults in mid-gestation.

DESIGN

An analytical, observational, and cross-sectional study.

SETTING

Public health system in the city of Blumenau, Brazil.

PARTICIPANTS

Primigravidae adolescents under the age of 16 and adults over age 20 (n = 40/group) were systematically sampled.

INTERVENTIONS

Cervical measurements were performed between 21 and 24 weeks of gestation through transvaginal ultrasonography using a previously validated method.

MAIN OUTCOME MEASURES

Mean cervical length (Mann-Whitney test) and percentage of cervices below 25 mm (Fisher exact test).

RESULTS

For adolescents and adults, average uterine cervix lengths were 28 ± 6.6 mm 33 ± 4.1 mm (P < .0001), respectively, and the proportion of cervixes below 25 mm were 27.5% and 7.5% (P < .02), respectively. In addition, adolescents had significantly lower gynecologic age, education, and family income than adults.

CONCLUSION

Primigravida adolescents under the age of 16 have shorter cervices than adults, and a higher percentage of adolescents have cervices shorter than 25 mm. This may be associated with the higher risk of preterm birth observed in adolescents and suggests that this population requires special attention in prenatal care.

[What use of progesterone to prevent preterm birth?]

Widely prescribed in the years 1970-1980 to prolong gestation, progesterone has regained interest after the publication of randomized trials since 10 years. In women at increased risk of preterm birth with a history of preterm delivery or late miscarriage, the use of progesterone, especially intramuscularly may reduce the incidence of spontaneous preterm birth. In contrast, in cases of preterm labor or twin pregnancies, progesterone efficacy to reduce preterm birth has not been demonstrated. In women with asymptomatic midtrimester sonographic short cervix, randomized studies show conflicting results and new studies are necessary before its widespread utilisation.

Calcium channel blockers as tocolytics: principles of their actions, adverse effects and therapeutic combinations

Dihydropyridine Ca²⁺ channel blockers (CCBs) are widely accepted in the treatment of premature labour. Their mechanism of action in tocolysis involves the blockade of L-type Ca²⁺ channels, influenced by the Ca²⁺-activated K⁺ channels, beta-adrenergic receptors (β-ARs) and sexual hormones. In clinical practice, most experience has been gained with the use of nifedipine, whose efficacy is superior or comparable to those of β-agonists and oxytocin antagonists. Additionally, it has a favourable adverse effect profile as compared with the majority of other tocolytics. The most frequent and well-tolerated side-effects of CCBs are tachycardia, headache and hypotension. In tocolytic therapy efforts are currently being made to find combinations of tocolytic agents that yield better therapeutic action. The available human and animal studies suggest that the combination of CCBs with β-AR agonists is beneficial, although such combinations can pose risk of pulmonary oedema in multiple pregnancies and maternal cardiovascular diseases. Preclinical data indicate the potential benefit of combinations of CCBs and oxytocin antagonists. However, the combinations of CCBs with progesterone or cyclooxygenase inhibitors may decrease their efficacy. The CCBs are likely to remain one of the most important groups of drugs for the rapid inhibition of premature uterine contractions. Their significance may be magnified by further clinical studies on their combined use for tocolysis.

Preventing preterm births: analysis of trends and potential reductions with interventions in 39 countries with very high human development index

BACKGROUND

Every year, 1·1 million babies die from prematurity, and many survivors are disabled. Worldwide, 15 million babies are born preterm (<37 weeks' gestation), with two decades of increasing rates in almost all countries with reliable data. The understanding of drivers and potential benefit of preventive interventions for preterm births is poor. We examined trends and estimate the potential reduction in preterm births for countries with very high human development index (VHHDI) if present evidence-based interventions were widely implemented. This analysis is to inform a rate reduction target for Born Too Soon.

METHODS

Countries were assessed for inclusion based on availability and quality of preterm prevalence data (2000-10), and trend analyses with projections undertaken. We analysed drivers of rate increases in the USA, 1989-2004. For 39 countries with VHHDI with more than 10,000 births, we did country-by-country analyses based on target population, incremental coverage increase, and intervention efficacy. We estimated cost savings on the basis of reported costs for preterm care in the USA adjusted using World Bank purchasing power parity.

FINDINGS

From 2010, even if all countries with VHHDI achieved annual preterm birth rate reductions of the best performers for 1990-2010 (Estonia and Croatia), 2000-10 (Sweden and Netherlands), or 2005-10 (Lithuania, Estonia), rates would experience a relative reduction of less than 5% by 2015 on average across the 39 countries. Our analysis of preterm birth rise 1989-2004 in USA suggests half the change is unexplained, but important drivers include non-medically indicated labour induction and caesarean delivery and assisted reproductive technologies. For all 39 countries with VHHDI, five interventions modelling at high coverage predicted a 5% relative reduction of preterm birth rate from 9·59% to 9·07% of livebirths: smoking cessation (0·01 rate reduction), decreasing multiple embryo transfers during assisted reproductive technologies (0·06), cervical cerclage (0·15), progesterone supplementation (0·01), and reduction of non-medically indicated labour induction or caesarean delivery (0·29). These findings translate to roughly 58,000 preterm births averted and total annual economic cost savings of about US$3 billion.

INTERPRETATION

We recommend a conservative target of a relative reduction in preterm birth rates of 5% by 2015. Our findings highlight the urgent need for research into underlying mechanisms of preterm births, and development of innovative interventions. Furthermore, the highest preterm birth rates occur in low-income settings where the causes of prematurity might differ and have simpler solutions such as birth spacing and treatment of infections in pregnancy than in high-income countries. Urgent focus on these settings is also crucial to reduce preterm births worldwide.

FUNDING

March of Dimes, USA, Eunice Kennedy Shriver National Institute of Child Health and Human Development, and National Institutes of Health, USA.

Critical appraisal of the efficacy, safety, and patient acceptability of hydroxyprogesterone caproate injection to reduce the risk of preterm birth

Prevention of preterm delivery is a major desiderate in contemporary obstetrics and a societal necessity. The means to achieve this goal remain elusive. Progesterone has been used in an attempt to prevent preterm delivery since the 1970s, but the evidence initially accumulated was fraught by mixed results and was based on mostly underpowered studies with variable eligibility criteria, including history of spontaneous abortion as an indication for treatment. More recent randomized controlled clinical trials restimulated the interest in progesterone supplementation, suggesting that progesterone may favorably influence the rate of preterm delivery. Preterm delivery is a complex disorder and consequently it is unlikely that one generalized prevention strategy will be effective in all patients. Further, an additional impediment in accepting progesterone as the "magic bullet" in the prevention of preterm delivery is that its mechanism of action is not fully understood and the optimal formulations, route of administration, and dose have yet to be established. We have concerned ourselves in this review with the most recent status of 17 alpha-hydroxyprogesterone caproate (17OH-PC) supplementation for prevention of preterm delivery. Our intention is to emphasize the efficacy, safety, and patient acceptability of this intervention, based on a comprehensive and unbiased review of the available literature. Currently there are insufficient data to suggest that 17OH-PC is superior or inferior to natural progesterone. Based on available evidence, we suggest a differential approach giving preferential consideration to either 17OH-PC or other progestins based on obstetric history and cervical surveillance. Progestin therapy for risk factors other than a history of preterm birth and/or a short cervix in the current pregnancy is not currently supported by the published evidence. The experience to date with 17OH-PC indicates that there are population subgroups that may be harmed by administration of 17OH-PC. Therefore, extending the use of 17OH-PC to unstudied populations or for indications that are not evidence-based is inadvisable outside of a research protocol.

Transabdominal evaluation of uterine cervical length during pregnancy fails to identify a substantial number of women with a short cervix

OBJECTIVE

To assess the diagnostic performance of transabdominal sonographic measurement of cervical length in identifying patients with a short cervix.

METHODS

Cervical length was measured in 220 pregnant women using transabdominal and transvaginal ultrasound (US). Reproducibility and agreement between and within both methods were assessed. The diagnostic accuracy of transabdominal US for identifying cases with a cervical length <25 mm was evaluated.

RESULTS

Twenty-one out of 220 cases (9.5%) had a cervical length <25 mm by transvaginal US. Only 43% (n = 9) of patients with a short cervix were correctly identified by transabdominal US. In patients with a cervical length of <25 mm by transvaginal US, transabdominal measurement of the cervix overestimated this parameter by an average of 8 mm (95% LOAs, -26.4 to 10.5 mm). Among women without a short cervix, transabdominal US underestimated cervical length on average (LOA) by 1.1 mm (95% LOAs, -11.0 to 13.2 mm). Transvaginal US was also more reproducible (intraclass correlation coefficient: (ICC) (0.96; 95% CI, 0.94 to 0.97) based on comparisons between 2D images and immediately acquired 3D volume datasets relative to transabdominal US (ICC: 0.71; 95% CI, 0.57 to 0.84). Transvaginal US detected 13 cases with funneling and six cases with sludge whereas only three cases of funneling and one of sludge were detected by transabdominal US.

CONCLUSION

Transabdominal measurement overestimated cervical LOA by 8 mm among women with a short cervix and resulted in the underdiagnosis of 57% of cases.

Effect of prolonged in vivo administration of progesterone in pregnancy on myometrial gene expression, peripheral blood leukocyte activation, and circulating steroid hormone levels

OBJECTIVE

We aimed to investigate the effects of progesterone on gene expression and function of both myometrium and circulating leukocytes.

METHODS

We recruited women participating in a randomized clinical trial of progesterone to prevent preterm delivery. These participants had a twin pregnancy and were managed in 1 of 2 tertiary referral centers. Participants were treated with progesterone (90 mg vaginally) or placebo from 24 to 34 weeks of pregnancy. The outcome measures were myometrial and leukocyte gene expression and expression of cell surface markers in circulating leukocytes, all quantified ex vivo.

RESULTS

Prolonged in vivo administration of progesterone inhibited myometrial expression of connexins 26 and 43, endothelial nitric acid synthase (eNOS), and the prostaglandin receptor EP2 ex vivo. Administration of progesterone also increased numbers of circulating neutrophils while decreasing lymphocyte proportions and decreasing neutrophil CD11b expression.

CONCLUSION

The observed effects of prolonged in vivo administration of progesterone will minimize the ability of the uterus to contract as a synctium and the ability of peripheral blood leukocytes to migrate into the myometrium during parturition. We suggest that these are putative mechanisms by which progesterone might prevent preterm birth in women at high risk.

Trial protocol OPPTIMUM-- does progesterone prophylaxis for the prevention of preterm labour improve outcome?

BACKGROUND

Preterm birth is a global problem, with a prevalence of 8 to 12% depending on location. Several large trials and systematic reviews have shown progestogens to be effective in preventing or delaying preterm birth in selected high risk women with a singleton pregnancy (including those with a short cervix or previous preterm birth). Although an improvement in short term neonatal outcomes has been shown in some trials these have not consistently been confirmed in meta-analyses. Additionally data on longer term outcomes is limited to a single trial where no difference in outcomes was demonstrated at four years of age of the child, despite those in the "progesterone" group having a lower incidence of preterm birth.

METHODS/DESIGN

The OPPTIMUM study is a double blind randomized placebo controlled trial to determine whether progesterone prophylaxis to prevent preterm birth has long term neonatal or infant benefit. Specifically it will study whether, in women with singleton pregnancy and at high risk of preterm labour, prophylactic vaginal natural progesterone, 200 mg daily from 22 - 34 weeks gestation, compared to placebo, improves obstetric outcome by lengthening pregnancy thus reducing the incidence of preterm delivery (before 34 weeks), improves neonatal outcome by reducing a composite of death and major morbidity, and leads to improved childhood cognitive and neurosensory outcomes at two years of age. Recruitment began in 2009 and is scheduled to close in Spring 2013. As of May 2012, over 800 women had been randomized in 60 sites.

DISCUSSION

OPPTIMUM will provide further evidence on the effectiveness of vaginal progesterone for prevention of preterm birth and improvement of neonatal outcomes in selected groups of women with singleton pregnancy at high risk of preterm birth. Additionally it will determine whether any reduction in the incidence of preterm birth is accompanied by improved childhood outcome.

TRIAL REGISTRATION

ISRCTN14568373.

Development of a prognostic model for predicting spontaneous singleton preterm birth

OBJECTIVE

To develop and validate a prognostic model for prediction of spontaneous preterm birth.

STUDY DESIGN

Prospective cohort study using data of the nationwide perinatal registry in The Netherlands. We studied 1,524,058 singleton pregnancies between 1999 and 2007. We developed a multiple logistic regression model to estimate the risk of spontaneous preterm birth based on maternal and pregnancy characteristics. We used bootstrapping techniques to internally validate our model. Discrimination (AUC), accuracy (Brier score) and calibration (calibration graphs and Hosmer-Lemeshow C-statistic) were used to assess the model's predictive performance. Our primary outcome measure was spontaneous preterm birth at <37 completed weeks.

RESULTS

Spontaneous preterm birth occurred in 57,796 (3.8%) pregnancies. The final model included 13 variables for predicting preterm birth. The predicted probabilities ranged from 0.01 to 0.71 (IQR 0.02-0.04). The model had an area under the receiver operator characteristic curve (AUC) of 0.63 (95% CI 0.63-0.63), the Brier score was 0.04 (95% CI 0.04-0.04) and the Hosmer Lemeshow C-statistic was significant (p<0.0001). The calibration graph showed overprediction at higher values of predicted probability. The positive predictive value was 26% (95% CI 20-33%) for the 0.4 probability cut-off point.

CONCLUSIONS

The model's discrimination was fair and it had modest calibration. Previous preterm birth, drug abuse and vaginal bleeding in the first half of pregnancy were the most important predictors for spontaneous preterm birth. Although not applicable in clinical practice yet, this model is a next step towards early prediction of spontaneous preterm birth that enables caregivers to start preventive therapy in women at higher risk.

Characteristics of children with cerebral palsy in the ORACLE children study

AIMS

We have identified an excess of children with cerebral palsy (CP) born to women who received antibiotic treatment for spontaneous preterm labour (SPL). This nested study investigated the profile of impairment among children with CP in the ORACLE Children Study (OCS), and contrasted outcomes with those in 4Child, a population CP registry.

METHOD

The study group comprised 167 children aged from 7 to 10 years (100 males, 67 females) with CP from the OCS, who were subdivided into a preterm rupture of membranes (PROM) group (87 children) and an SPL group (80 children). The OCS sought follow-up information regarding the health and behaviour of surviving children at 7 years of age in the UK using a parent-report postal questionnaire. Families provided further information to define wider aspects of function and were offered a physiotherapy assessment.

RESULTS

The prevalence of CP was higher among children in the OCS than among those in 4Child (standardized morbidity ratios: SPL group, 3.12 [95% confidence interval {CI} 2.47-3.87); PROM group: 1.56 (CI 1.24-1.92)]. The proportion of children with CP born after 32 weeks of gestation was higher in in the SPL group (73%) than in the PROM group (30%); the prevalence of CP was higher in the SPL group than in the PROM group or 4Child. Children with CP in the OCS tended to have similar distributions of neuroimpairment as children in 4Child, but motor impairment and associated vision and hearing problems were found to be less severe.

INTERPRETATION

The pattern of CP in both the PROM and the SPL groups was similar, but functional outcomes were milder, compared with children with CP in the general population. However, in these groups the risk of CP was increased independently of gestational age. This is consistent with findings that ongoing inflammatory damage can cause CP.

Use of progestogens in pregnant and infertile patients

Progesterone is an essential hormone in the occurence and maintenance of pregnancy. Natural or synthetic progestogens are commonly used in pregnant patients or patients undergoing infertility treatments for various indications. Most frequently put indications for the use of progestogens in these patient populations are the prevention of spontaneous preterm birth, the prevention of pregnancy loss in pregnancies with an unexplained recurrent pregnancy loss and in patients with threatened abortion. It is also used in pregnant women undergoing nonobstetric surgery, for infertility or recurrent pregnancy loss that is thought to be due to luteal phase defect or as a luteal support in stimulated IVF cycles. We aimed to review the current evidence for the use of progestogens in each of these settings.

Successful pregnancy in a patient suffering from recurrent mid-trimester miscarriage with C9 deficiency after receiving cervical cerclage followed by clindamycin and progesterone: a case report

Complement component 9 (C9) deficiency is relatively common, especially in Japan. Here we present the case of a 27-year-old Japanese woman whose obstetric history involved three mid-trimester miscarriages (at 22 weeks', 18 weeks' and 21 weeks' gestation) and one early spontaneous miscarriage. Her fifth pregnancy was successfully managed by cervical cerclage at 13 weeks' gestation, followed by clindamycin administration (600 mg/day for 7 days) and progesterone injections (250 mg/week). She gave birth to a healthy 3326-g male infant at 40 weeks and 1 day gestation after natural onset of labor. After delivery, the serum complement components were analyzed. C9 protein and activity were undetectable in the patient's serum. We suggest that an immunologic disorder such as C9 deficiency should be considered as a potential complication of undiagnosed recurrent miscarriages.