A woman with preeclampsia gave birth vaginally 1 hour ago. She is still receiving a magnesium sulfate infusion at 1 gm/hr. A major concern regarding the administration of magnesium sulfate at this time would be:

A. The cervix is effacing and dilated to 2 cm. Cervical changes, including effacement and dilation, are the most definitive signs of preterm labor. Uterine contractions alone do not confirm preterm labor unless they result in cervical dilation, indicating that labor is progressing.

B. Irregular, mild uterine contractions are occurring every 15-30 minutes. Irregular contractions, known as Braxton Hicks contractions, can be common in pregnancy and do not necessarily indicate preterm labor. True preterm labor involves regular contractions that lead to cervical changes.

C. Estriol is not found in maternal saliva. The absence of estriol in maternal saliva does not confirm or rule out preterm labor. Salivary estriol testing is not a widely used or reliable diagnostic tool for determining the onset of preterm labor.

D. Fetal fibronectin is present in vaginal secretion. Fetal fibronectin (fFN) is a protein found in vaginal secretions between 22-34 weeks of pregnancy and can indicate a risk of preterm labor, but its presence alone does not confirm that labor is actively occurring. A positive fFN test means the patient may be at increased risk for preterm labor, but cervical changes remain the best indicator of actual labor.

A. Oligohydramnios. Oligohydramnios, or low amniotic fluid levels, is not a primary complication of pregestational diabetes. It is more commonly associated with conditions such as fetal growth restriction, post-term pregnancy, and rupture of membranes rather than maternal hyperglycemia.

B. Congenital fetal anomalies. Poor glycemic control during preconception and early pregnancy increases the risk of congenital anomalies, particularly affecting the heart, spine, and central nervous system. Hyperglycemia during organogenesis (first 8 weeks of gestation) can lead to defects such as neural tube defects and cardiac malformations.

C. Intrauterine fetal seizures. Fetal seizures in utero are extremely rare and are not a common complication of maternal diabetes. While neonatal hypoglycemia after birth can lead to seizures, maternal hyperglycemia does not directly cause seizures in the fetus.

D. Polyhydramnios. While polyhydramnios (excess amniotic fluid) can occur in pregnancies complicated by diabetes due to fetal polyuria, it is more associated with later pregnancy. The question specifically asks about preconception and early pregnancy risks, making congenital anomalies the best answer.