Induced abortion - impact on a subsequent pregnancy in first-time mothers: a registry-based study

To date, several studies concerning the effects of induced abortion (IA) on women's later psychosocial well-being and future delivery complications have been published. However, the lack of reports on woman's physical well-being during their first full-term pregnancy occurring after IA is what inspired the current study. Here, we evaluate the physical well-being and use of maternity services of first-time mothers with a history of IA.

Finnish National Birth Registry data from 2008 to 2010 were linked with the Induced Abortion Registry data from 1983 to 2007. After excluding first-time mothers with a history of miscarriage, ectopic pregnancy or delivery, 57,406 mothers were eligible for the study, with 5,167 (9.0 %) having experienced prior IA. Data from the pregnancy follow-up visits were evaluated and compared between IA mothers and primiparous mothers.

Women with IA had higher rates of smoking after the first trimester and were more likely to be overweight (body mass index >25 kg/m²) than the control group mothers. A higher use of maternity health clinic (MHC) services, thrombosis prophylaxis and participation in a second trimester ultrasound and amniotic fluid sample testing were evident in IA mothers, whereas the likelihood of assisted fertilisation procedure(s) was elevated in the control group. A shorter interpregnancy interval (IPI) seemed to contribute to a late first MHC visit and first trimester serum screening test participation, a higher incidence of placenta samples and an increased presence of preeclampsia and maternal care for poor foetal growth.

IA is associated with being overweight before the subsequent pregnancy and with smoking after the first trimester. More frequent pregnancy follow-up visits in the IA group may be due to greater participation in the placenta sample testing and use of thrombosis prophylaxis. No association between IA and preeclampsia, hypertension, gestational diabetes or preterm premature rupture of membranes was evident in the pregnancy parameters. According to our findings, experiencing IA decreased the need for fertilisation procedures before the next pregnancy when compared to primiparous mothers. Among the IA mothers, the short IPI seemed to contribute to the higher risk for preeclampsia and maternal care for poor foetal growth. However, more research is needed around the IPI before establishing its effect on later pregnancy.