Assisted reproductive technologies and the risk of stillbirth in singleton pregnancies: a systematic review and meta-analysis

Incidence and first trimester risk factors of stillbirth in Indonesia

OBJECTIVES

To determine the incidence and the risk factors of stillbirth from maternal biophysical, ultrasound, and biochemical markers at 11-13 weeks of gestation in the Indonesian population.

METHODS

This was a retrospective cohort study of pregnant women for first-trimester preeclampsia screening at 11-13 weeks of gestation in some clinics and hospital in Jakarta. Maternal characteristics and history, mean arterial pressure (MAP) measurement, uterine artery pulsatility index (UtA-PI) ultrasound, maternal ophthalmic peak ratio (Oph-PR) Doppler, and placental growth factor (PlGF) serum were collected during the visit. Stillbirth was classified into placental dysfunction-related when it occurred with preeclampsia or birth weight <10th percentile and non-placental dysfunction-related. Bivariate and multivariate logistic regression analyses were employed to determine the risk factors associated with stillbirth.

RESULTS

Of 1,643 eligible participants, 13 (0.79 %) stillbirth cases were reported. More than half of the stillbirths (7) were placental dysfunction-related. After adjusted with maternal age, body mass index (BMI), and parity status, chronic hypertension (aOR (adjusted odds ratio)) 24.41, 95 % CI {confidence interval} 5.93-100.43), previous pregnancy with preeclampsia (aOR 15.79, 95 % CI 4.42-56.41), MAP >101.85 (aOR 26.67, 95 % CI 8.26-86.06), UtA-PI >1.90 (aOR 10.68, 95 % CI 2.34-48.58, and PlGF <28.77 pg/mL (aOR 18.60, 95 % CI 5.59-61.92) were associated with stillbirth.

CONCLUSIONS

The incidence of stillbirth in the population is comparable to studies conducted in developed countries. Most routine variables assessed at the 11-13 weeks combined screening for preeclampsia are associated with the risk of stillbirth.

Stillbirth: we can do better

Stillbirth is far too common, occurring in millions of pregnancies per year globally. The rate of stillbirth (defined as death of a fetus prior to birth at 20 weeks' gestation or more) in the United States is 5.73 per 1000. This is approximately 1 in 175 pregnancies accounting for about 21,000 stillbirths per year. Although rates are much higher in low-income countries, the stillbirth rate in the United States is much higher than most high resource countries. Moreover, there are substantial disparities in stillbirth, with rates twice as high for non-Hispanic Black and Native Hawaiian or Other Pacific Islanders compared to non-Hispanic Whites. There is considerable opportunity for reduction in stillbirths, even in high resource countries such as the United States. In this article, we review the epidemiology, risk factors, causes, evaluation, medical and emotional management, and prevention of stillbirth. We focus on novel data regarding genetic etiologies, placental assessment, risk stratification, and prevention.

Ovulation induction and subfertile untreated conception groups offer improved options for interpreting risks associated with ART

PURPOSE

To identify and characterise appropriate comparison groups for population studies of health outcomes in ART-conceived births: ovulation induction (OI), subfertile untreated and fertile natural conceptions. Our secondary objective was to examine whether known risks of pregnancy complications and adverse birth outcomes in ART births are elevated in comparison with subfertile (untreated and OI) conception groups.

METHODS

We linked State and Commonwealth datasets to identify all live and stillbirths (≥ 20 weeks) in Western Australia from 2003 to 2014 by method of conception. Demographic characteristics, maternal pre-existing conditions, adverse obstetric history and pregnancy complications were compared across conception groups. Generalised estimating equations were used to estimate adjusted risk ratios (aRRs) and 95% confidence intervals (CI) for pregnancy complications and birth outcomes in singletons.

RESULTS

We identified 9456 ART, 3870 OI, 11,484 subfertile untreated and 303,921 fertile naturally conceived deliveries. OI and subfertile untreated groups more closely resembled the ART group than the fertile group; however, some differences remained across parity, maternal age, pre-existing conditions and obstetric history. In multivariate analyses, ART singletons had greater risks of placental problems (e.g. placenta praevia aRR 2.42 (95% CI 1.82-3.20)) and adverse birth outcomes (e.g. preterm birth aRR 1.38 (95% CI 1.25-1.52)) than the subfertile untreated group, while OI singletons were more similar to the subfertile group with higher risk of preeclampsia and gestational diabetes.

CONCLUSION

OI and subfertile untreated conception groups offer improved options for interpreting health outcomes in ART births. Pregnancy complications (particularly placental disorders) and adverse outcomes at delivery are more common following ART.

Pregnancies through oocyte donation. A mini review of pathways involved in placental dysfunction

Pregnancies resulting from assisted reproductive techniques (ART) are increasingly prevalent worldwide. While most pregnancies conceived through in-vitro fertilization (IVF) progress without complications, mounting evidence suggests that these pregnancies are at a heightened risk of adverse perinatal outcomes. Specifically, IVF pregnancies involving oocyte donation have garnered attention due to numerous reports indicating an elevated risk profile for pregnancy-related complications within this subgroup of patients. The precise mechanisms contributing to this increased risk of complications remain incompletely understood. Nonetheless, it is likely that they are mediated by an abnormal immune response at the fetal-maternal interface. Additionally, these outcomes may be influenced by baseline patient characteristics, such as the etiology of infertility, absence of corpus luteum, and variations in endometrial preparation protocols, among other factors. This review aims to succinctly summarize the most widely accepted mechanisms that potentially contribute to the onset of placental dysfunction in pregnancies conceived through oocyte donation.

Effects of the Zishen Yutai Pill compared with placebo on pregnancy outcomes among women in a fresh embryo transfer cycle: a Post Hoc subgroup analysis of a randomized controlled trial

Objective

To assess whether the administration of Zishen Yutai Pill (ZYP) could improve the pregnancy outcomes in different subgroups of women undergoing fresh embryo transfer cycles.

Materials and methods

This is a post hoc analysis of a large scale, placebo-controlled, double blind, randomized clinical trial (RCT) regarding the use of ZYP during assisted reproductive technology (ART) treatment. The RCT was conducted at 19 in vitro fertilization (IVF) centers between April 2014 and June 2017. A total of 2265 women undergoing fresh embryo transfer cycles were randomly assigned in a 1:1 ratio to receive ZYP (n = 1131) or placebo (n = 1134). Post hoc logistic regression analyses were applied in this study to examine the between-group differences of ZYP and placebo on clinical pregnancy rate among different subgroups. Detailed analyses, both in intention-to-treat (ITT) and per-protocol population, were also conducted in specific subgroups with regards to rates of implantation, biochemical pregnancy, clinical pregnancy, live birth, pregnancy loss, as well as other neonatal indices.

Results

ZYP showed a significantly higher clinical pregnancy rates than placebo in the ITT population. Detailed subgroup analyses were conducted in subgroup in advanced maternal age (AMA, ≥ 35 years old) and overweight/obese patients (BMI > 24), due to the clinical importance and statistical results. In these subgroups, baseline characteristics were similar between two arms (all P > 0.05). Significantly elevated clinical pregnancy rates were observed in ZYP cohort (both P < 0.05) compared with the placebo group. Results also showed that ZYP treatment resulted in significantly higher rates of implantation, biochemical pregnancy in AMA or overweight/obese patients in ITT analysis (all P < 0.05).

Conclusions

The current post hoc subgroup analysis suggested that AMA and overweight/obese women could experience clinical benefits when treated with ZYP in their fresh embryo transfer cycles. The study provides references for the use of ZYP in ART practices. However, further studies in specific subgroups should be examined in more rigorous clinical trial settings.

Clinical trial registration

Chictr.org.cn, ChictrTRC-14004494.

Impact of Assisted Reproduction Techniques on Adverse Maternal Outcomes and on the Rate of Hospitalization in Maternal Intensive Care

Background and Objective: The aim of this retrospective cohort study is to evaluate the impact of assisted reproductive treatment (ART) on adverse maternal outcomes and the rate of hospitalization in maternal intensive care (MIC) in a tertiary university center in Liege, Belgium. Materials and Methods: This is a retrospective cohort study comparing two groups, 6557 patients who achieved pregnancy spontaneously and 330 patients who achieved pregnancy after ART, between January 2020 and December 2022. These patients were followed in the academic obstetrics department of Citadelle Hospital, Liège. The database of the ART center was compared with the database of the delivery unit to determine the cohort of patients who conceived after ART. Adverse maternal outcomes and MIC hospitalization rates were compared with between spontaneous pregnancies and ART groups. ART groups were also compared with each other. Results: The rate of hospitalization in maternal intensive care for patients who achieved pregnancy spontaneously was 12.1%, compared to 17.3% after ART. Comparing the rate of pre-eclampsia, 3.5% of spontaneous pregnancies were complicated by pre-eclampsia, while after ART, 10.9% of patients developed this complication during pregnancy. This rate was higher after IVF (12%) compared to intrauterine insemination and particularly after frozen embryo transfer (FET) in artificial cycle (17.9%). The birthweight of newborns after ART was also analyzed. A significant difference was obtained when comparing fresh embryo transfer with FET. Conclusions: Our study confirmed that FET in artificial cycle is a risk factor for pre-eclampsia and that fresh embryo transfer is associated with a higher rate of newborns with a lower percentile of birthweight. Our data showed that the rate of MIC hospitalization was significantly higher after ART but did not differ between groups.

Obesity as a potential risk factor for stillbirth: The Japan Environment and Children's Study

The relationship between high body mass index (BMI) >25 kg/m2 and risk for stillbirth in the Japanese population remains unclear. This study aimed to estimate the impact of maternal obesity on the risk of stillbirth in a Japanese population. This prospective cohort study used data from the Japan Environment and Children's Study, which recruited pregnant individuals between 2011 and 2014. A total of 93,772 fetuses were considered eligible for inclusion in this study. Stillbirth (fetal death before or during labor at ≥22 completed weeks of gestation) rates were compared among four pre-pregnancy BMI groups: underweight (<18.5 kg/m2), reference (18.5 to <25.0 kg/m2), overweight (25.0 to <30.0 kg/m2), and obese (≥30.0 kg/m2). The association between pre-pregnancy BMI and the risk of stillbirth was estimated using multiple logistic regression analyses. The overall stillbirth incidence was 0.33% (305/93,722). Compared with the reference group, the risk of stillbirth was significantly higher in the overweight group (adjusted odds ratio [aOR]: 1.55; 95% confidence interval [CI]: 1.08-2.23) and the obese group (aOR: 2.60; 95% CI: 1.59-4.24). The overall incidence of early stillbirth (i.e., <28 weeks) was 0.17% (155/93,722). Similarly, after adjusting for potential confounding factors, the risk of early stillbirth was significantly higher in the obese group (aOR: 4.33; 95% CI: 2.44-7.70). Increased maternal BMI was associated with an increased risk of stillbirth in the Japanese population. Therefore, counselling women planning for pregnancy on the importance of an appropriate pre-pregnancy BMI to minimize the risk of stillbirth is important.

Gestational Age and Birth Outcomes in Term Singleton Pregnancies Conceived With Infertility Treatment

Importance

Despite the increased perinatal risks associated with pregnancies conceived with infertility treatment, there are no recommendations for timing of delivery among this at-risk population.

Objective

To identify the gestational age at which the ongoing risks of stillbirth are optimally balanced with the risks of neonatal comorbidities and infant deaths in term singleton pregnancies conceived with infertility treatment.

Design, Setting, and Participants

This cohort study used birth and death data from January 1, 2014, to December 31, 2018, in the US obtained from the National Center for Health Statistics. Singleton pregnancies conceived with infertility treatment delivered at term (37-42 weeks' gestation) were eligible for inclusion. The exclusion criteria were deliveries at less than 37 weeks' or at least 43 weeks' gestation and pregnancies with unknown history of infertility treatment, congenital anomalies, pregestational diabetes, pregestational hypertension, gestational hypertension, and preeclampsia. Data were analyzed from July 22, 2022, to June 24, 2023.

Exposure

Gestational age at delivery between 37 and 42 weeks.

Main Outcomes and Measures

The primary outcome was optimal timing of delivery. To ascertain this timing, the risk of delivery (rate of neonatal morbidity and infant death) at a given gestational week was compared with the risk of delivery in the subsequent week of gestation for an additional week (rate of stillbirth during the given week per 10 000 ongoing pregnancies plus rate of neonatal morbidity and infant death in the subsequent week of gestation per 10 000 deliveries). The rates of stillbirth, neonatal morbidity, and infant death (within 1 year of life) were compared at each week. Neonatal morbidity included an Apgar score of 3 or lower at 5 minutes, requirement of ventilation for 6 hours or more, neonatal intensive care unit admission, and seizures.

Results

Of the 178 448 singleton term pregnancies conceived with infertility treatment (maternal mean [SD] age, 34.2 [5.2] years; mean [SD] gestational age, 39.2 [1.2] weeks; 130 786 [73.5%] were non-Hispanic White patients). The risk of delivery in the subsequent week of gestation was lower than the risk of delivery at both 37 weeks (628 [95% CI, 601-656] vs 1005 [95% CI, 961-1050] per 10 000 live births) and 38 weeks (483 [95% CI, 467-500 vs 625 [95% CI, 598-652] per 10 000 live births). The risks of delivery in subsequent week of gestation significantly exceeded the risk of delivery at 39 weeks (599 [95% CI, 576-622] vs 479 [95% CI, 463-495] per 10 000 live births) and were not significant at 40 weeks (639 [95% CI, 605-675] vs 594 [95% CI, 572-617] per 10 000 live births) and 41 weeks (701 [95% CI, 628-781] vs 633 [95% CI, 599-669] per 10 000 live births).

Conclusions and Relevance

Results of this study suggest that, in pregnancies conceived with infertility treatment, delivery at 39 weeks provided the lowest perinatal risk when comparing risk of delivery at this week of gestation vs the subsequent week of gestation.

Fetal Growth Velocity according to the Mode of Assisted Conception

INTRODUCTION

Pregnancies conceived through assisted reproductive techniques (ARTs) are on the rise worldwide and have been associated with a higher risk of placental-related disease in the third trimester.

METHODS

A cohort was created of singleton pregnancies after assisted reproduction, admitted at our institution for delivery, between January 2020 and August 2022. Fetal growth velocity from the second trimester to delivery was compared against a gestational-age-matched group of pregnancies spontaneously conceived according to the origin of the selected oocyte (i.e., autologous vs. donated).

RESULTS

125 singleton pregnancies conceived through ART were compared to 315 singleton spontaneous conceptions. Overall, after adjusting for possible confounders, multivariate analysis demonstrated that ART pregnancies had a significantly lower estimated fetal weight (EFW) z-velocity from the second trimester to delivery (adjusted mean difference = -0.002; p = 0.035) and a higher frequency of EFW z-velocity in the lowest decile (adjusted OR = 2.32 [95% CI, 1.15-4.68]). Also, when ART pregnancies were compared according to the type of oocyte, those conceived with donated oocytes showed a significantly lower EFW z-velocity from the second trimester to delivery (adjusted mean difference = -0.008; p = 0.001) and a higher frequency of EFW z-velocity in the lowest decile (adjusted OR = 5.33 [95% CI, 1.34-21.5]).

CONCLUSIONS

Pregnancies achieved through ART exhibit a pattern of lower growth velocity across the third trimester, especially those conceived with donated oocytes. The former represents a sub-group at the highest risk of placental dysfunction that may warrant closer follow-up.

Perinatal and pediatric outcomes associated with the use of fertility treatment: a population-based retrospective cohort study in Ontario, Canada

BACKGROUND

Around 2% of births in Ontario, Canada involve the use of assisted reproductive technology (ART), and it is rising due to the implementation of a publicly funded ART program in 2016. To better understand the impact of fertility treatments, we assessed perinatal and pediatric health outcomes associated with ART, hormonal treatments, and artificial insemination compared with spontaneously conceived births.

METHODS

This population-based retrospective cohort study was conducted using provincial birth registry data linked with fertility registry and health administrative databases in Ontario, Canada. Live births and stillbirths from January 2013 to July 2016 were included and followed to age one. The risks of adverse pregnancy, birth and infant health outcomes were assessed by conception method (spontaneous conception, ART - in vitro fertilization and non-ART - ovulation induction, intra-uterine or vaginal insemination) using risk ratios and incidence rate ratios with 95% confidence intervals (CI). Propensity score weighting using a generalized boosted model was applied to adjust for confounding.

RESULT(S)

Of 177,901 births with a median gestation age of 39 weeks (IQR 38.0-40.0), 3,457 (1.9%) were conceived via ART, and 3,511 (2.0%) via non-ART treatments. There were increased risks (adjusted risk ratio [95% CI]) of cesarean delivery (ART: 1.44 [1.42-1.47]; non-ART: 1.09 [1.07-1.11]), preterm birth (ART: 2.06 [1.98-2.14]; non-ART: 1.85 [1.79-1.91]), very preterm birth (ART: 2.99 [2.75-3.25]; non-ART: 1.89 [1.67-2.13]), 5-min Apgar < 7 (ART: 1.28 [1.16-1.42]; non-ART: 1.62 [1.45-1.81]), and composite neonatal adverse outcome indicator (ART: 1.61 [1.55-1.68]; non-ART: 1.29 [1.25-1.34]). Infants born after fertility treatments had increased risk of admission to neonatal intensive care unit (ART: 1.98 [1.84-2.13]; non-ART: 1.59 [1.51-1.67]) and prolonged birth admission (≥ 3 days) (ART: 1.60 [1.54-1.65]; non-ART: 1.42 [1.39-1.45]). The rate of emergency and in-hospital health services use within the first year was significantly increased for both exposure groups and remained elevated when limiting analyses to term singletons.

CONCLUSION(S)

Fertility treatments were associated with increased risks of adverse outcomes; however, the overall magnitude of risks was lower for infants conceived via non-ART treatments.

Reproductive outcomes in women and men conceived by assisted reproductive technologies in Norway: prospective registry based study

Objectives

To determine whether the perinatal outcomes of women or men who were conceived by assisted reproductive technologies are different compared with their peers who were naturally conceived.

Design

Prospective registry based study.

Setting

Medical Birth Registry of Norway.

Participants

People born in Norway between 1984 and 2002 with a registered pregnancy by the end of 2021.

Exposure

People who were conceived by assisted reproductive technologies and have had a registered pregnancy.

Main outcome measures

Comparing pregnancies and births of people who were conceived by assisted reproductive technologies and people who were naturally conceived, we assessed mean birth weight, gestational age, and placental weight by linear regression, additionally, the odds of congenital malformations, a low 5 min Apgar score (<7), transfer to a neonatal intensive care unit, delivery by caesarean section, use of assisted reproductive technologies, hypertensive disorders of pregnancy and pre-eclampsia, preterm birth, and offspring sex, by logistic regression. The occurrence of any registered pregnancy from people aged 14 years until age at the end of follow-up was assessed using Cox proportional regression for both groups.

Results

Among 1 092 151 people born in Norway from 1984 to 2002, 180 652 were registered at least once as mothers, and 137 530 as fathers. Of these, 399 men and 553 women were conceived by assisted reproductive technologies. People who were conceived by assisted reproductive technologies had little evidence of increased risk of adverse outcomes in their own pregnancies, increased use of assisted reproductive technologies, or any difference in mean birth weight, placental weight, or gestational age. The only exception was for an increased risk of the neonate having a low Apgar score at 5 min (adjusted odds ratio 1.86 (95% confidence interval 1.20 to 2.89)) among women who were conceived by assisted reproductive technologies. Odds were slightly decreased of having a boy among mothers conceived by assisted reproductive technologies (odds ratio 0.79 (95% confidence interval 0.67 to 0.93)). People conceived by assisted reproductive technologies were slightly less likely to have a registered pregnancy within the follow-up period (women, adjusted hazard ratio 0.88 (95% CI 0.81 to 0.96); men, 0.91 (0.83 to 1.01)).

Conclusions

People conceived by assisted reproductive technologies were not at increased risk of obstetric or perinatal complications when becoming parents. The proportion of people conceived by assisted reproductive technologies with a registered pregnancy was lower than among people who were naturally conceived, but a longer follow-up is required to fully assess their fertility and reproductive history.

Is telephone follow-up reliable in maternal and neonatal outcomes surveys in in vitro fertilization?

BACKGROUND

 Many studies that collect maternal and neonatal outcomes rely on patient self-report phone calls. It is unclear how reliable or accurate these phone call reports are.

OBJECTIVE

To evaluate the reliability of telephone calls in information collection in IVF.

STUDY DESIGN

The women were interviewed seven days after delivery by a nurse via telephone. The maternal and neonatal outcomes were recorded based on a self-report from one of the spouses. Meanwhile, the standardized electronic hospitalized discharge records were extracted from the hospital medical database. For each case, maternal and neonatal information obtained from telephone interviews and extracted from medical files were compared.

RESULTS

Agreement was classified as "almost perfect, K = 0.81-1.00" for preterm birth, cesarean delivery, low birth weight baby, and macrosomia. The strength of agreement was classified as "moderate, K = 0.41-0.60" for some antepartum complications: gestational diabetes (K = 0.569); pregnancy-induced hypertension (K = 0.588); intrahepatic cholestasis of pregnancy (K = 0.597) and oligohydramnios (K = 0.432). The strength of agreement between telephone interviews and hospitalized discharge records can be classified as "slight (K = 0-0.20)" for some complications: thyroid diseases (K = 0.137), anemia (K = 0.047), postpartum hemorrhage (K = 0.016), and Fetal distress (K = 0.106).

CONCLUSION

Some variables (preterm birth, cesarean delivery, birth weight) information collected by telephone follow-up were reliable. However, other complications (thyroid diseases, anemia, postpartum hemorrhage, and fetal distress) collected via self-report was non-reliable. Compared with complications during labor, antepartum complications have higher agreement between different follow-up methods. IVF records and hospitalized discharge records should be matched and collected simultaneously when discussing maternal and neonatal outcomes of IVF.

Temporal trends and adverse perinatal outcomes of twin pregnancies at differing gestational ages: an observational study from China between 2012–2020

Background

With the development of assisted reproductive technology, the twinning rate in China has been increasing. However, little is known about twinning from 2014 onwards. In addition, previous studies analysing optimal gestational times have rarely considered maternal health conditions. Therefore, whether maternal health conditions affect the optimal gestational time remains unclear.

Methods

Data of women delivered between January 2012 and December 2020 were collected through China’s National Maternal Near Miss Surveillance System. Interrupted time series analysis was used to determine the rates of twinning, stillbirth, smaller than gestational age (SGA), and low Apgar scores (< 4) among twins in China. To estimate the risk of each adverse perinatal outcome for separate gestational weeks, a multivariate generalised linear model was used. Infants born at 37 weeks of gestational age or foetuses staying in utero were used as reference separately. The analyses were adjusted for the sampling distribution of the population and the cluster effect at the hospital and individual levels were considered.

Results

There were 442,268 infants enrolled in this study, and the adjusted rates for twinning, stillbirth, SGA, and low Apgar scores were 3.10%, 1.75%, 7.70%, and 0.79%, respectively. From 2012 to 2020, the twinning rate showed an increasing trend. Adverse perinatal outcomes, including stillbirth, SGA, and low Apgar scores showed a decreasing trend. A gestational age between 34 and 36 weeks decreased most for rate of stillbirth (average changing rate -9.72%, 95% confidence interval [CI] -11.41% to -8.00%); and a gestational age of between 37 and 38 weeks decreased most for rates of SGA (average changing rate -4.64%, 95% CI -5.42% to -3.85%) and low Apgar scores (average changing rate -17.61%, 95% CI -21.73% to -13.26%). No significant difference in changes in twinning rate or changes of each perinatal outcome was observed during periods of different fertility policies. Infants born at 37 weeks of gestation had a decreased risk of stillbirth, SGA, and low Apgar scores. Maternal antepartum or medical complications increased the risk of SGA and low Apgar scores in different gestational weeks.

Conclusion

China’s twinning rate showed an increasing trend, while adverse perinatal outcomes decreased from 2012 to 2020. Fertility policy changes have had little effect on the twinning rate or the rate of adverse perinatal outcomes such as stillbirth, SGA, or low Apgar scores. The optimal gestational age for twins was 37 weeks. Women pregnant with twins and with antepartum or medical complications should be cautious due to an increased risk of SGA and low Apgar scores.

Predicting singleton antepartum stillbirth by the demographic Fetal Medicine Foundation Risk Calculator—A retrospective case-control study

Objective

To assess the risk of singleton intrauterine fetal death (IUFD) in women by the demographic setting of the online Fetal Medicine Foundation (FMF) Stillbirth Risk Calculator.

Methods

Retrospective single-centre case-control study involving 144 women having suffered IUFD and 247 women after delivery of a live-born singleton. Nonparametric receiver operating characteristics (ROC) analyses were performed to predict the prognostic power of the FMF Stillbirth risk score and to generate a cut-off value to discriminate best between the event of IUFD versus live birth.

Results

Women in the IUFD cohort born a significantly higher overall risk with a median FMF risk score of 0.45% (IQR 0.23–0.99) compared to controls [0.23% (IQR 0.21–0.29); p<0.001]. Demographic factors contributing to an increased risk of IUFD in our cohort were maternal obesity (p = 0.002), smoking (p<0.001), chronic hypertension (p = 0.015), antiphospholipid syndrome (p = 0.017), type 2 diabetes (p<0.001), and insulin requirement (p<0.001). ROC analyses showed an area under the curve (AUC) of 0.72 (95% CI 0.67–0.78; p<0.001) for predicting overall IUFD and an AUC of 0.72 (95% CI 0.64–0.80; p<0.001), respectively, for predicting IUFD excluding congenital malformations. The FMF risk score at a cut-off of 0.34% (OR 6.22; 95% CI 3.91–9.89; p<0.001) yielded an 82% specificity and 58% sensitivity in predicting IUFD with a positive and negative predictive value of 0.94% and 99.84%, respectively.

Conclusion

The FMF Stillbirth Risk Calculator based upon maternal demographic and obstetric characteristics only may help identify women at low risk of antepartum stillbirth.

Obesity Class Impacts Adverse Maternal and Neonatal Outcomes Independent of Diabetes

INTRODUCTION

Obesity in pregnancy is a known risk factor for adverse maternal and neonatal outcomes. Few studies have compared adverse pregnancy-related outcomes according to obesity severity. Hence, we aimed to examine the impact of obesity class on maternal and perinatal outcomes.

METHODS

We retrospectively analysed data from all singleton births from mothers with obesity from 2013-2017 in Northern Sydney Local Health District in Sydney, Australia. Women were categorised into obesity class I (BMI 30-34.9kg/m2), class II (BMI 35-39.9 kg/m2) or class III (BMI 40+ kg/m2). Across BMI classes, we compared maternal outcomes including mode of delivery, gestational diabetes mellitus (GDM), and preeclampsia, and neonatal outcomes including large- and small-for-gestational age (SGA, LGA), neonatal hypoglycaemia, birth defects and timing of birth. Logistic analyses were performed to explore the impact of maternal obesity class on these outcomes, adjusting for maternal age, country of birth, parity, diabetes (both pre-existing and gestational) and hypertension.

RESULTS

There were 2466 births to women with obesity, class (69.1%), class II (21.8%), and class III (9.2%). 42.5% delivered by Caesarean section, 22.3% developed GDM and 11.2% had a hypertensive disorder in pregnancy, and Caesarean section and GDM were more common in women with higher class obesity. LGA occurred in 27.3% and SGA occurred in 4.0% of women across all classes of obesity. LGA rates were 49% more likely in women with class III compared to women with class I obesity (OR=1.49, CI 1.06-2.09, p=0.02). The presence of diabetes in the index pregnancy did not significantly impact risk of neonatal LGA between maternal obesity classes. Other neonatal adverse outcomes such as stillbirth and birth defects were more common in women with higher class obesity. SGA, neonatal hypoglycaemia, gestational age at delivery, APGAR 5-minute score and NICU admissions were similar across obesity classes, after adjustment for covariates.

CONCLUSIONS

Obesity class increases the risk of many adverse maternal and neonatal outcomes. Obesity class is independently associated with LGA incidence in the neonate, independent of maternal factors including GDM. Ongoing efforts must be made to reduce obesity incidence in women of reproductive age to circumvent the adverse perinatal outcomes associated with obesity.

Current Resources for Evidence-Based Practice, January 2022

An extensive review of new resources to support the provision of evidence-based care for women and infants. The current column includes a discussion of breastfeeding while employed and commentaries on reviews focused on mammography test characteristics and sexual health for gynecologic cancer survivors. It also includes a quick update on a USPSTF review for aspirin as pre-eclampsia prophylaxis.