Vaginal progesterone vs intramuscular 17α-hydroxyprogesterone caproate for prevention of recurrent spontaneous preterm birth in singleton gestations: systematic review and meta-analysis of randomized controlled trials

Risk of spontaneous preterm birth in IVF-conceived twin pregnancies

OBJECTIVE

To compare the mean transvaginal ultrasound (TVU) cervical length (CL) at midtrimester in screening for preterm birth in in vitro (IVF)-conceived twin pregnancies versus spontaneously-conceived twin pregnancies.

METHODS

This was a retrospective cohort study. Potential study subjects were identified at the time of a routine second trimester fetal ultrasound exam at 18 0/7 to 23 6/7-week gestation. All women with twin diamniotic pregnancies screened with a single TVU CL for this trial were included. Mean TVU CLs were compared between IVF-conceived twin pregnancies and spontaneously-conceived twin pregnancies. The relationship of TVU CL with gestational age at delivery was assessed. Incidence of short TVU CL, defined as TVU CL ≤30 mm, was also calculated in the two groups. The primary outcome was the mean of TVU CL. Distribution of CL was determined and normality was examined in both groups Results: A total of 668 women with diamniotic twin pregnancies who underwent TVU CL screening between 18 0/6 and 23 6/7 weeks were included. 158 (23.7%) were IVF-conceived pregnancies, and 510 (76.3%) were spontaneously-conceived pregnancies. No women received progesterone, pessary, or cerclage for preterm birth prevention during pregnancy. The mean TVU CL was significantly lower in the IVF-conceived group (32.2 ± 10.5 mm) compared to the spontaneously-conceived group (34.1 ± 9.1 mm) (mean difference (MD) - 1.90 mm, 95%CI -3.72 to -0.08). The incidence of TVU CL ≤30 mm was 30.4% in the IVF-conceived group and 21.6% in the spontaneously-conceived group (adjusted odds ratio (aOR) 1.59, 95%CI 1.06-2.37). IVF-conceived twins had a significantly higher risk of spontaneous preterm birth <34 weeks (32.9 versus 21.2%; aOR 1.83, 95% confidence interval (CI) 1.23-2.71) and higher rate of delivery due to spontaneous onset of labor (64.5 versus 54.9%; aOR 1.50, 95%CI 1.03-2.17). For any given TVU CL measured between 18 0-7 and 23 6/7 weeks, gestational age at delivery for IVF-conceived twins was earlier by about 1 week on average compared with spontaneously-conceived twins.

CONCLUSIONS

The higher rate of spontaneous preterm birth in IVF-conceived twin pregnancies is predicted by lower midtrimester TVU CL, as well as by the lower gestational age at birth per any given CL in the IVF-conceived compared to the spontaneously-conceived twin pregnancies.

Use of progesterone supplement therapy for prevention of preterm birth: review of literatures

Preterm birth (PTB) is one of the most common complications during pregnancy and it primarily accounts for neonatal mortality and numerous morbidities including long-term sequelae including cerebral palsy and developmental disability. The most effective treatment of PTB is prediction and prevention of its risks. Risk factors of PTB include history of PTB, short cervical length (CL), multiple pregnancies, ethnicity, smoking, uterine anomaly and history of curettage or cervical conization. Among these risk factors, history of PTB, and short CL are the most important predictive factors. Progesterone supplement therapy is one of the few proven effective methods to prevent PTB in women with history of spontaneous PTB and in women with short CL. There are 2 types of progesterone therapy currently used for prevention of PTB: weekly intramuscular injection of 17-alpha hydroxyprogesterone caproate and daily administration of natural micronized progesterone vaginal gel, vaginal suppository, or oral capsule. However, the efficacy of progesterone therapy to prevent PTB may vary depending on the administration route, form, dose of progesterone and indications for the treatment. This review aims to summarize the efficacy and safety of progesterone supplement therapy on prevention of PTB according to different indication, type, route, and dose of progesterone, based on the results of recent randomized trials and meta-analysis.

Recent advances in the prevention of preterm birth

Preterm birth (PTB) remains a major obstetric healthcare problem and a significant contributor to perinatal morbidity, mortality, and long-term disability. Over the past few decades, the perinatal outcomes of preterm neonates have improved markedly through research and advances in neonatal care, whereas rates of spontaneous PTB have essentially remained static. However, research into causal pathways and new diagnostic and treatment modalities is now bearing fruit and translational initiatives are beginning to impact upon PTB rates. Successful PTB prevention requires a multifaceted approach, combining public health and educational programs, lifestyle modification, access to/optimisation of obstetric healthcare, effective prediction and diagnostic modalities, and the application of effective, targeted interventions. Progress has been made in some of these areas, although there remain areas of controversy and uncertainty. Attention is now being directed to areas where greater gains can be achieved. In this mini-review, we will briefly and selectively review a range of PTB prevention strategies and initiatives where progress has been made and where exciting opportunities await exploitation, evaluation, and implementation.

Interventions for treating hyperemesis gravidarum: a Cochrane systematic review and meta-analysis

INTRODUCTION

While nausea and vomiting in early pregnancy are very common, affecting approximately 80% of the pregnancies, hyperemesis gravidarum is a severe form affecting 0.3-1.0% of the pregnancies. Although hyperemesis gravidarum is rarely a source of mortality, it is a significant source of morbidity. It is one of the most common indications for hospitalization in pregnancy. Beyond the maternal and fetal consequences of malnutrition, the severity of hyperemesis symptoms causes a major psychosocial burden leading to depression, anxiety, and even pregnancy termination. The aim of this meta-analysis was to examine all randomized controlled trials of interventions specifically for hyperemesis gravidarum and evaluate them based on both subjective and objective measures of efficacy, maternal and fetal/neonatal safety, and economic costs.

MATERIAL AND METHODS

Randomized controlled trials were identified by searching electronic databases. We included all randomized controlled trials for the treatment of hyperemesis gravidarum. The primary outcome was intervention efficacy as defined by severity, reduction, or cessation in nausea/vomiting; number of episodes of emesis; and days of hospital admission. Secondary outcomes included other measures of intervention efficacy, adverse maternal/fetal/neonatal outcomes, quality of life measures, and economic costs.

RESULTS

Twenty-five trials (2052 women) met the inclusion criteria but the majority of 18 different comparisons described in the review include data from single studies with small numbers of participants. Selected comparisons reported below: No primary outcome data were available when acupuncture was compared with placebo. There was insufficient evidence to identify clear differences between acupuncture and metoclopramide in a study with 81 participants regarding reduction/cessation in nausea or vomiting (risk ratio (RR) 1.40, 95% CI 0.79-2.49 and RR 1.51, 95% CI 0.92-2.48, respectively). Midwife-led outpatient care was associated with fewer hours of hospital admission than routine inpatient admission (mean difference (MD) - 33.20, 95% CI -46.91 to -19.49) with no difference in pregnancy-unique quantification of emesis and nausea (PUQE) score, decision to terminate the pregnancy, miscarriage, small-for-gestational age infants, or time off work when compared with routine care. Women taking vitamin B6 had a slightly longer hospital stay compared with placebo (MD 0.80 days, 95% CI 0.08-1.52). There was insufficient evidence to demonstrate a difference in other outcomes including mean number of episodes of emesis (MD 0.50, 95% CI -0.40-1.40) or side effects. A comparison between metoclopramide and ondansetron identified no clear difference in the severity of nausea or vomiting (MD 1.70, 95% CI -0.15-3.55, and MD -0.10, 95% CI -1.63-1.43; one study, 83 women, respectively). However, more women taking metoclopramide complained of drowsiness and dry mouth (RR 2.40, 95% CI 1.23-4.69, and RR 2.38, 95% CI 1.10-5.11, respectively). There were no clear differences between groups for other side effects. In a single study with 146 participants comparing metoclopramide with promethazine, more women taking promethazine reported drowsiness, dizziness, and dystonia (risk ratio (RR) 0.70, 95% CI 0.56-0.87, RR 0.48, 95% CI 0.34-0.69, and RR 0.31, 95% CI 0.11-0.90, respectively). There were no clear differences between groups for other important outcomes including quality of life and other side effects. In a single trial with 30 women, those receiving ondansetron had no difference in duration of hospital admission compared to those receiving promethazine (mean difference (MD) 0.00, 95% CI -1.39-1.39), although there was increased sedation with promethazine (RR 0.06, 95% CI 0.00-0.94). Regarding corticosteroids, in a study with 110 participants there was no difference in days of hospital admission compared to placebo (MD -0.30, 95% CI -0.70-0.10), but there was a decreased readmission rate (RR 0.69, 95% CI 0.50-0.94; 4 studies, 269 women). For hydrocortisone compared with metoclopramide, no data were available for primary outcomes and there was no difference in the readmission rate (RR 0.08, 95% CI 0.00-1.28; one study, 40 women). In a study with 80 women, compared to promethazine, those receiving prednisolone had increased nausea at 48 h (RR 2.00, 95% CI 1.08-3.72), but not at 17 days (RR 0.81, 95% CI 0.58-1.15). There was no clear difference in the number of episodes of emesis or subjective improvement in nausea/vomiting.

CONCLUSIONS

While there were a wide range of interventions studied, both pharmaceutical and otherwise, there were a limited number of placebo controlled trials. In comparing the efficacy of the commonly used antiemetics, metoclopramide, ondansetron, and promethazine, the results of this review do not support the clear superiority of one over the other in symptomatic relief. Other factors such as side effect profile medication safety and healthcare costs should also be considered when selecting an intervention.

Implementing universal cervical length screening in asymptomatic women with singleton pregnancies: challenges and opportunities

Cervical length (CL) screening has been successfully utilised to identify asymptomatic women, with a singleton pregnancy, at risk of preterm birth (PTB), thereby providing an opportunity to offer interventions that may reduce that risk. Cervical length screening with ultrasound is most effectively performed with a transvaginal approach. Universal cervical length screening, encompassing all singleton pregnancies rather than restricting screening to those considered at increased risk of PTB, is currently not widely used, despite a growing body of evidence in support of its utility for PTB prevention. There are a number of barriers that may prevent or restrict the implementation of a universal CL screening program. These include cost, availability of vaginal progesterone and other treatment options, reluctance of women to undergo transvaginal ultrasound and the perceptions and beliefs of medical practitioners. Given that mid-pregnancy CL measurement is a recognised predictor of spontaneous PTB, that most cases of PTB occur with no prior maternal history and that there are interventions available that may reduce the risk of PTB, we believe there is a clear role for routine CL screening to be adopted as a component of the fetal morphology ultrasound examination. As a strategy to reduce PTB rates, discussion and counselling about PTB prevention and CL screening should be adopted as a core element of prenatal care.