Methods

Participants

This hospital-based nested case-control study was based on a longitudinal GHOACS conducted at the Obstetrics and Gynaecology Department of Komfo Anokye Teaching Hospital (KATH). Both nulliparous and multiparous normotensive pregnant women (NTN-PW) aged from 18 to 45 years with a singleton pregnancy at 10-20 weeks gestation, that provided written informed consent, were recruited at baseline.
Sociodemographic data were obtained through a completed questionnaire, and clinical and obstetric data were obtained from the antenatal folder and participant’s record in the database of the KATH. The overall health of participants at visit 1 was assessed using the Suboptimal Health Questionnaire-25 (SHSQ-25) and pregnant women were classified as SHS and OHS based on the procedure described in previous studies.16, 17
At the start of the study, defined as wave 1 (W1) (10-20 weeks gestation, median, 17 weeks), 593 clinically diagnosed normotensive pregnant women (NTN-PW) were included. Of the 593, 504 returned to participate in the first follow-up, wave 2 (W2) (21-31 weeks gestation, median 27 weeks), whereas 498 completed the study, wave 3 (W3) (32-42 weeks gestation) and were included in the final assessment. At the time of delivery (32-42 weeks gestation), 197 had developed PE and were classified as cases whereas 301 returned as NTN-PW and were classified as controls. Of the 498 participants, 248 of them had ‘SHS’ at baseline of which 153 later developed PE (56 EO-PE and 97 LO-PE) and 95 returned as NTN-PW. Also, 250 had ‘optimal health status’(OHS) at baseline of which 44 developed PE (14 EO-PE and 30 LO-PE) and 206 returned as NTN-PW. A total of 95 women were lost to follow-up due to unwillingness to continue (n=32), relocation (n=48), spontaneous abortion (n=4) and self-induced abortion (n=11) (Figure 1).
Figure 1. Study participants.