Background
Sexually transmitted infections (STIs) during pregnancy are associated with adverse pregnancy outcomes. We evaluated the impact of diagnosing and treating curable STIs (Chlamydia [CT]/Gonorrhoea [NG]) during pregnancy on adverse pregnancy outcomes among women in a HIV pre-exposure prophylaxis (PrEP) cohort study in Cape Town, South Africa.
Methods
Eligible women >16 years, attending antenatal care, without HIV, received HIV prevention counselling, diagnostic testing with Gene-Xpert (point-of-care (POC)) (Aug 2019-Nov 2020) or laboratory (Dec 2020-Oct 2021) and treatment for CT/NG and were offered oral PrEP at enrolment and follow-up visits. We compared pregnancy loss (miscarriage [<20 weeks] or stillbirth [>20 weeks]) and birth outcomes (low birthweight (LBW) [<2500grams], preterm delivery (PTD) [<37weeks], small for gestational age (SGA) [<10th percentile] and neonatal death [<7days]) among women diagnosed with or without CT/NG at study enrolment. Logistic regression models assessed the association between STI diagnosis, time to treatment and adverse pregnancy outcomes adjusting for maternal age, relationship status, gravidity and gestational age.
Results
Among 1261 pregnant women, 28% had CT/NG at enrolment (24% for CT and 8% for NG). Of those with CT/NG (n=353), 54% received immediate treatment, 34% delayed treatment (median time to treatment 28 days; IQR: 15-57 days) and 12% were not treated during pregnancy. Of 1244 women with singleton pregnancies, outcomes were: 42 (3%) miscarriage, 31 (2%) stillbirth and 1171 (93%) live births (including 72 (6%) preterm and 50 (5%) low birthweight). Proportions of miscarriage and stillbirth were highest in women with untreated CT/NG (12% and 9%), lower in women with CT/NG and delayed treatment (4% and 3%), and lowest among women with CT/NG and immediate treatment (1% and 2%). In women with CT/NG, untreated STI was associated with increased odds of pregnancy loss (aOR=3.89, 95% CI: 1.51-9.97) compared to STI with immediate treatment. In all women, untreated CT/NG was associated with increased odds of pregnancy loss (aOR=4.27, 95% CI: 1.95-9.34) compared to no STI.
Conclusions
Pregnant women without HIV in a PrEP cohort study diagnosed with CT/NG (POC or laboratory) and remained untreated during pregnancy had higher odds of miscarriage or stillbirth compared to those without STI or who received immediate treatment. Our results suggest important benefits of POC screening and immediate treatment of curable STIs in pregnancy in improving outcomes.