Table 1.
Adverse obstetric and neonatal outcomes according to the discrepancy between pregnancy dating methods (n = 1 100 049).
| Prevalence (n/100 000 births) | Large negative discrepancy n = 119 275 | Small negative discrepancy n = 238 929 | Small positive discrepancy n = 110 952 | Large positive discrepancy n = 113 236 | |||||
|---|---|---|---|---|---|---|---|---|---|
| OR | (95% CI) | OR | (95% CI) | OR | (95% CI) | OR | (95% CI) | ||
| Pregnancy or delivery outcomes | |||||||||
| Preeclampsia | 3377 | 1.23 | (1.19–1.27) | 1.13 | (1.10–1.16) | 0.96 | (0.93–1.00) | 0.97 | (0.94–1.01) |
| Diabetes mellitus in pregnancy | 1459 | 1.46 | (1.39–1.53) | 1.20 | (1.16–1.25) | 0.87 | (0.82–0.93) | 0.86 | (0.81–0.91) |
| Prolonged second stage of labor | 720 | 0.90 | (0.84–0.98) | 0.88 | (0.83–0.94) | 1.10 | (1.02–1.18) | 1.11 | (1.03–1.19) |
| Delivery by forceps or vacuum extractor* | 6564 | 0.88 | (0.85–0.90) | 0.90 | (0.88–0.92) | 1.10 | (1.07–1.13) | 1.11 | (1.09–1.14) |
| Delivery by cesarean section | 13289 | 0.92 | (0.90–0.94) | 0.93 | (0.92–0.95) | 1.02 | (1.00–1.03) | 1.00 | (0.98–1.02) |
| Delivery by emergency cesarean section** | 6778 | 0.95 | (0.93–0.97) | 0.95 | (0.94–0.97) | 1.03 | (1.00–1.06) | 1.02 | (1.00–1.05) |
| Shoulder dystocia* | 202 | 1.12 | (0.97–1.28) | 0.95 | (0.85–1.07) | 1.02 | (0.88–1.18) | 1.16 | (1.01–1.33) |
| Postpartum hemorrhage | 5661 | 0.92 | (0.90–0.95) | 0.93 | (0.91–0.95) | 1.06 | (1.04–1.09) | 1.13 | (1.10–1.16) |
| Perineal laceration: third or fourth degree* | 3100 | 0.85 | (0.82–0.88) | 0.88 | (0.85–0.90) | 1.12 | (1.08–1.16) | 1.13 | (1.09–1.17) |
| Neonatal outcomes | |||||||||
| Apgar score < 7 at 5 minutes | 557 | 1.18 | (1.09–1.27) | 1.03 | (0.97–1.10) | 0.91 | (0.83–1.00) | 1.00 | (0.91–1.10) |
| Birth asphyxia | 987 | 1.18 | (1.11–1.25) | 1.03 | (0.98–1.08) | 1.02 | (0.96–1.09) | 1.07 | (1.00–1.14) |
| Intrauterine fetal death | 274 | 1.47 | (1.32–1.64) | 1.24 | (1.14–1.36) | 0.87 | (0.75–0.99) | 0.89 | (0.77–1.01) |
| Neonatal death (<28 days) | 141 | 2.19 | (1.91–2.50) | 1.26 | (1.10–1.43) | 0.89 | (0.73–1.08) | 1.00 | (0.82–1.20) |
| Small for gestational age (<2 SDs) | 2169 | 1.54 | (1.48–1.60) | 1.31 | (1.26–1.35) | 0.81 | (0.77–0.86) | 0.82 | (0.78–0.87) |
| Large for gestational age (>2 SDs) | 3617 | 1.10 | (1.06–1.14) | 1.04 | (1.01–1.07) | 1.02 | (0.99–1.06) | 1.02 | (0.99–1.06) |
Logistic regression-derived crude ORs and 95% CIs for adverse obstetric and neonatal outcomes among all recorded singleton births in Sweden 1995–2010, with documentation of the date of last menstrual period, US-based estimated date of delivery, maternal weight, and height according to the discrepancy between pregnancy dating methods. Negative discrepancy indicates that the EDD by LMP was at an earlier date than was the EDD by US. Positive discrepancy indicates that the EDD by LMP was at a later date. A large negative discrepancy was defined as below the 10th percentile, and a large positive discrepancy as above the 90th percentile in the discrepancy distribution. The reference category (n = 517 657) was a discrepancy within 2 days of the median. The intermediate groups were defined as small negative and small positive discrepancies.
*Excluding deliveries by cesarean section; **Excluding elective cesarean section.
OR, odds ratio; CI, confidence interval; EDD, estimated delivery date; LMP, last menstrual period; US, ultrasound; SD, standard deviation.