Table 1.
Baseline characteristics and pregnancy outcomes in participants excluding those of losing follow-up or artificial abortion in early pregnancy.
| Characteristic | Vaccinated group (165) | % | No-vaccination group (717) | % | P-value |
|---|---|---|---|---|---|
| Age, mean (SD),y | |||||
| <35 | 137/165 | 594/717 | |||
| ≥35 | 28/165 | 16.97 | 123/717 | 17.15 | 0.955 |
| Body mass index (kg/m2) | |||||
| Normal (<24 kg/m2) | 139/165 | 613/717 | |||
| Overweight (≥24 kg/m2) | 26/165 | 15.76 | 104/717 | 14.50 | 0.682 |
| Previous miscarriage | 21/165 | 12.73 | 122/717 | 17.02 | 0.178 |
| Twin pregnancy | 1/165 | 0.61 | 3/717 | 0.42 | 0.746 |
| Uterine anatomy | 1/165 | 0.61 | 3/717 | 0.42 | 0.746 |
| Nulliparous | 119/165 | 72.12 | 590/717 | 82.29 | 0.003 |
| Pregnancy loss | |||||
| Miscarriage | 20/165 | 12.12 | 89/717 | 12.41 | 0.918 |
| Stillbirth | 1/119 | 0 | |||
| Neonatal death | 0 | 0 | |||
| Birth defect | 1/120 | 0.83 | 5/514 | 1.00 | 0.887 |
| Congenital anomalies | 1 | 2 | |||
| Chromosome abnormality | 0 | 3 |
The denominator of the birth defect rate in the vaccination group included live-born infants. A total of 119 women in the study group delivered their babies, including one twin, during the study period. One case of congenital anomaly, i.e., atrial septal defect, was recorded in the vaccinated group, and the baby was still alive.
The denominator of the birth defect rate in the nonvaccinated group included live-born infants, and 511 women delivered their babies, including three twins, during the study period. Three cases of chromosomal abnormalities in the nonvaccinated group included two cases of trisomy 21 and one case of Noonan syndrome, which were manually terminated. Two cases of congenital malformations in the nonvaccinated group included one case of loss of the corpus callosum and one case of a solid mass in the right abdomen of the fetus, which were also manually terminated.
The denominator of stillbirth in the vaccination group was the number of live birth.