Clinical characteristics and pregnancy outcomes in three groups
Age range of participants was 18 to 46 years, the mean age was 29.63 years (SD=6.89) in confirmed and probable groups and 30.89 (6.85) in control group (P=0.045).Among all participants, 88.3%of women were in the third trimester of pregnancy that 82.9% and 58.3% and 92.4% of them were in confirmed, probable and control groups respectively. Interestingly, probable grouphad lower gestational age [30.09 (11.01)] in comparison with confirmed [33.43 (7.50) and control groups [36.57 (5.30)] (P< 0.001). There were no differences between these groups regarding clinical characteristics and past medical and obstetric history (Table 2). Furthermore, confirmed cases had almost the same frequency of pre-existing medical problems (13.51%) compared to probable cases (8.33%) and control group (12.03%) (p=0.688). It should be noted that since hypothyroidism was common in all three groups, especially in the control group, we did not classify hypothyroidism with other underlying diseases in the same category to prevent its confounding effect.
The unadjusted and adjusted estimates for total maternal and neonatal outcomes are presented in Table 3. CS was carried out in total 96 women (52.74%, 95%CI: 45.22, 68.31). Although unadjusted results showed significantly higher rate of CS in probable group compared with confirmed and control groups, after adjusting for potential confounders, no significant differences were found in terms of delivery type between confirmed and probable groups (aRR: 1.24, 95%CI: 0.93, 1.65, P= 0.138) and also between probable and control groups (aRR: 1.55, 95%CI: 0.85, 2.82, P= 0.152), so, there was no difference between groups according to delivery type. In addition, no significant association was found between COVID-19 infection and preterm labor(PTL), gestational diabetes mellitus (GDM), preeclampsia , intra uterine growth restriction(IUGR),preterm rupture of membrane (PROM),stillbirth, postpartum haemorrhage and postpartum infection. Furthermore, there were no significant differences between three groups in terms of essential neonatal outcomes including low birth weight, NICU admission, neonatal sepsis, APGAR score at one and 5 minutes (Tables 3 and 4).In our study, only one infant had a positive Covid-19 PCR test after birth, and the other infants had negative results. Considering this issue that the baby was completely isolated and separated from the mother immediately after birth, there is a possibility of vertical transmission in this baby, but anyway, since we did not examine the umbilical cord blood and amniotic fluid in terms of virus culture, we cannot definitively claim that there has been a vertical transmission in this baby