What is the main reason why a woman who is older than 35 years may have difficulty achieving pregnancy?

Choice A reason: Cerebral compression is the cause of early decelerations, as it reflects the fetal head compression during uterine contractions. Early decelerations are decreases in the FHR that begin and end with the onset and end of a contraction, respectively. They are symmetrical and mirror the shape of the contraction. Early decelerations are normal and benign, as they indicate that the fetus is responding to the increased intracranial pressure and maintaining adequate oxygenation.

Choice B reason: Cord compression is not the cause of early decelerations but of variable decelerations. Variable decelerations are abrupt and irregular decreases in the FHR that vary in onset, duration, and depth. They are usually caused by the umbilical cord being compressed or occluded by the fetal body, the maternal pelvis, or the uterine contractions. Variable decelerations can indicate fetal distress or hypoxia, especially if they are severe, frequent, or prolonged.

Choice C reason: Uteroplacental insufficiency is not the cause of early decelerations, but of late decelerations. Late decelerations are decreases in the FHR that begin after the peak of a contraction and return to the baseline after the contraction ends. They are symmetrical and have a gradual onset and recovery. They are usually caused by the reduced blood flow and oxygen delivery to the placenta and the fetus due to maternal or fetal factors. Late decelerations can indicate fetal distress or hypoxia, and require immediate intervention.

Choice D reason: Spontaneous rupture of membranes is not the cause of early decelerations, but it can be a risk factor for cord compression and variable decelerations. Spontaneous rupture of membranes is the breaking of the amniotic sac and the release of the amniotic fluid, which usually occurs during labor or shortly before it. Spontaneous rupture of membranes can cause the umbilical cord to prolapse or slip into the vagina, where it can be compressed or kinked by the fetal head or the contractions.

Choice A reason: Normal weight women should gain 11.5 to 16 kg during pregnancy, according to the Institute of Medicine (IOM) guidelines. This is based on the body mass index (BMI) of 18.5 to 24.9 before pregnancy.

Choice B reason: Underweight women should gain 12.5 to 18 kg during pregnancy, according to the IOM guidelines. This is based on the BMI of less than 18.5 before pregnancy. Underweight women are at risk of having low birth weight infants, so they need to gain more weight to support fetal growth and development.

Choice C reason: Adolescents are encouraged to strive for weight gains at the upper end of the recommended scale, according to the IOM guidelines. This is because adolescents are still growing themselves and need extra nutrients and calories to meet their own needs and those of the fetus.

Choice D reason: In twin gestations, the weight gain recommended for a single fetus pregnancy should not be simply doubled. The IOM guidelines suggest that women with twin gestations should gain 16.5 to 24.5 kg if they have a normal weight before pregnancy, 14 to 22.5 kg if they are overweight, and 11 to 19 kg if they are obese.

Choice E reason: Obese women should gain at least 7 to 11.5 kg during pregnancy, according to the IOM guidelines. This is based on the BMI of 30 or more before pregnancy. Obese women are at risk of having complications such as gestational diabetes, preeclampsia, and cesarean delivery, so they need to limit their weight gain to avoid further complications.