Seasonality of adverse birth outcomes in women with and without HIV in a representative birth outcomes surveillance study in Botswana

A time-stratified, case-crossover study of heat exposure and perinatal mortality from 16 hospitals in sub-Saharan Africa

Growing evidence suggests that extreme heat events affect both pregnant women and their infants, but few studies are available from sub-Saharan Africa. Using data from 138,015 singleton births in 16 hospitals in Benin, Malawi, Tanzania and Uganda, we investigated the association between extreme heat and early perinatal deaths, including antepartum and intrapartum stillbirths, and deaths within 24 h after birth using a time-stratified case-crossover design. We observed an association between an increase from the 75th to the 99th percentile in mean temperature 1 week (lag 0-6 d) before childbirth and perinatal mortality (odds ratio (OR) = 1.34 (95% confidence interval (CI) 1.01-1.78)). The estimates for stillbirths were similarly positive, but CIs included unity: OR = 1.29 (95% CI 0.95-1.77) for all stillbirths, OR = 1.18 (95% CI 0.71-1.95) for antepartum stillbirths and OR = 1.64 (95% CI 0.74-3.63) for intrapartum stillbirths. The cumulative exposure-response curve suggested that the steepest slopes for heat for intrapartum stillbirths and associations were stronger during the hottest seasons. We conclude that short-term heat exposure may increase mortality risks, particularly for intrapartum stillbirths, raising the importance of improved intrapartum care.

Subsequent pregnancies in the IMPAACT 2010/VESTED Trial: high rate of adverse outcomes in women living with HIV

Introduction

Women with HIV (WHIV) have higher risks of adverse pregnancy outcomes, particularly in the absence of antiretroviral treatment(ART), and timing of ART may impact risk.

Methods

In IMPAACT 2010 (VESTED), 643 pregnant WHIV in 9 countries were randomized 1:1:1 to initiate ART: dolutegravir (DTG)+emtricitabine(FTC)/tenofovir alafenamide(TAF); DTG+FTC/tenofovir disoproxil fumarate (TDF) or efavirenz (EFV)/FTC/TDF. We describe adverse pregnancy outcomes in women with a subsequent pregnancy during 50 weeks of postpartum follow-up: spontaneous abortion (<20 weeks), stillbirth (≥20 weeks), preterm delivery (<37 weeks) and small-for-gestational-age (SGA).

Results

Of 643 women, 19 (3%) had 20 subsequent pregnancies while receiving ART at conception: DTG/FTC/TAF(3), DTG/FTC/TDF(2), EFV/FTC or lamivudine(3TC)/TDF(12), EFV/abacavir/3TC (1) and no ART(1). Four spontaneous abortions, 3 stillbirths, and 1 induced abortion occurred. Three (25%) of 12 liveborn infants were preterm (24-, 26- and 36-weeks' gestation). Only 12 (60%) subsequent pregnancies resulted in live birth, and at least 1 adverse pregnancy outcome occurred in 11/19 (58%) (induced abortion excluded). Of 7 women who experienced spontaneous abortion/stillbirth in the subsequent pregnancy, 4 experienced a stillbirth and 1 a neonatal death as outcomes of their earlier index pregnancy. No congenital anomalies were reported.

Conclusions

Adverse pregnancy outcomes were common in this cohort of WHIV who conceived on ART shortly after an index pregnancy, 35% ended in stillbirth or spontaneous abortion. The majority of fetal losses occurred in women with recent prior pregnancy loss. Data from larger cohorts of WHIV conceiving on ART and surveillance are needed to elucidate rates and predictors of adverse pregnancy outcome. (249 words).

Risk of Adverse Birth Outcomes in Two Cohorts of Pregnant Women With HIV in Zambia

BACKGROUND

A trial of progesterone to prevent preterm birth among HIV-infected Zambian women [Improving Pregnancy Outcomes with Progesterone (IPOP)] found no treatment effect, but the risk of the primary outcome was among the lowest ever documented in women with HIV. In this secondary analysis, we compare the risks of preterm birth (<37 weeks), stillbirth, and a composite primary outcome comprising the two in IPOP versus an observational pregnancy cohort [Zambian Preterm Birth Prevention Study (ZAPPS)] in Zambia, to evaluate reasons for the low risk in IPOP.

METHODS

Both studies enrolled women before 24 gestational weeks, during August 2015-September 2017 (ZAPPS) and February 2018-January 2020 (IPOP). We used linear probability and log-binomial regression to estimate risk differences and risk ratios (RR), before and after restriction and standardization with inverse probability weights.

RESULTS

The unadjusted risk of composite outcome was 18% in ZAPPS (N = 1450) and 9% in IPOP (N = 791) (RR = 2.0; 95% CI = 1.6, 2.6). After restricting and standardizing the ZAPPS cohort to the distribution of IPOP baseline characteristics, the risk remained higher in ZAPPS (RR = 1.6; 95% CI = 1.0, 2.4). The lower risk of preterm/stillbirth in IPOP was only partially explained by measured risk factors.

CONCLUSIONS

Possible benefits in IPOP of additional monetary reimbursement, more frequent visits, and group-based care warrant further investigation.

Maternal exposures to fine and ultrafine particles and the risk of preterm birth from a retrospective study in Beijing, China

Maternal exposure to fine particulate matter (PM_2.5) has been associated with increased risk of preterm birth (PTB), but evidence on particles in smaller sizes and PTB risk remains limited. In this retrospective analysis, we included birth records of 24,001 singleton live births from Haidian Maternal and Child Health Hospital in Beijing, China, 2014-2017. Concurrently, number concentrations of size-fractioned particles in size ranges of 5-560 nm (PNC_5-560) and mass concentrations of PM_2.5, black carbon (BC) and gaseous pollutants were measured from a fixed-location monitoring station in central Haidian District. Logistic regression models were used to estimate the odds ratio (OR) of air pollutants on PTB risk after controlling for temperature, relative humidity, and individual covariates (e.g., maternal age, ethnicity, gravidity, parity, gestational weight gain, fetal gender, the year and season of conception). Positive matrix factorization models were then used to apportion the sources of PNC_5-560. Among the 1062 (4.4%) PTBs, increased PTB risk was observed during the third trimester of pregnancy per 10 μg/m³ increase in PM_2.5 [OR = 1.92; 95% Confidence Interval (95% CI): 1.76, 2.09], per 1000 particles/cm³ increase in PNC_25-100 (OR = 1.09; 95% CI: 1.03, 1.15) and PNC_100-560 (OR = 1.22; 95% CI: 1.05, 1.42). Among the identified sources of PNC_5-560, emissions from gasoline and diesel vehicles were significantly associated with increased PTB risk, with ORs of 1.14 (95% CI: 1.01, 1.29) and 1.11 (95% CI: 1.04, 1.18), respectively. Exposures to other traffic-related air pollutants, such as BC and nitrogen dioxide (NO₂) were also significantly associated with increased PTB risk. Our findings highlight the importance of traffic emission reduction in urban areas.