Table 2.
Association between fetal sex and pregnancy complications. (n = 902,513).
| Outcomes | Male (%) (n = 464,075) | Female (%) (n = 438,438) | Crude RR (95% CI) | Adjusted RRa (95% CI) |
|---|---|---|---|---|
| Preeclampsia | 9265 (2.00) | 9502 (2.17) | 0.92 (0.89–0.95) | 0.92 (0.89–0.94) |
| HELLP syndrome | 565 (0.18) | 509 (0.17) | 1.05 (0.93–1.18) | 1.05 (0.93–1.18) |
| Placental abruption | 3946 (0.85) | 3250 (0.74) | 1.15 (1.10–1.20) | 1.15 (1.10–1.20) |
| Placenta accreta | 1941 (0.42) | 2040 (0.47) | 0.90 (0.84–0.96) | 0.90 (0.85–0.96) |
| Placenta previa | 7312 (1.58) | 6876 (1.57) | 1.00 (0.97–1.04) | 1.01 (0.97–1.04) |
| Intrauterine fetal death | 2641 (0.57) | 2446 (0.56) | 1.02 (0.97–1.08) | 1.02 (0.96–1.08) |
| Chorioamnionitis | 4187 (0.90) | 3843 (0.88) | 1.03 (0.99–1.08) | 1.03 (0.98–1.07) |
| Cord prolapse | 136 (0.04) | 104 (0.04) | 1.24 (0.96–1.60) | 1.24 (0.96–1.60) |
| Amniotic fluid embolism | 50 (0.01) | 51 (0.01) | 0.93 (0.63–1.37) | 0.93 (0.63–1.37) |
All risk ratios are calculated with females set as the reference.
RR risk ratio, CI confidence interval, HELLP hemolysis, elevated liver enzymes, low platelet count.
aAdjusted for maternal age, maternal height, maternal pre-pregnant body mass index, parity, conception method, and maternal smoking status during pregnancy.