What is the most dangerous effect on the fetus of a mother who smokes cigarettes while pregnant?

Choice A reason: Diabetes mellitus is not a direct consequence of inadequate weight gain during pregnancy for the infant. However, maternal diabetes can increase the risk of fetal macrosomia (large birth weight), congenital anomalies, and neonatal hypoglycemia (low blood sugar) in the infant.

Choice B reason: Down syndrome is not a direct consequence of inadequate weight gain during pregnancy for the infant. Down syndrome is a genetic disorder caused by an extra copy of chromosome 21 in the cells of the fetus. The risk of having a baby with Down syndrome increases with maternal age, but it is not related to maternal weight or nutrition².

Choice C reason: Spina bifida is not a direct consequence of inadequate weight gain during pregnancy for the infant. Spina bifida is a neural tube defect that occurs when the spine and spinal cord do not form properly in the fetus. The main risk factor for spina bifida is a lack of folic acid (a B vitamin) in the mother's diet before and during pregnancy.

Choice D reason: Intrauterine growth restriction (IUGR) is a condition in which the fetus does not grow as expected and has a low birth weight. IUGR can have many causes, such as placental problems, infections, chromosomal abnormalities, and maternal factors. One of the maternal factors that can contribute to IUGR is inadequate weight gain during pregnancy, especially in underweight women. IUGR can increase the risk of complications for the infant, such as preterm birth, low Apgar score, hypothermia, hypoglycemia, and breathing problems⁵.

The correct answer is d. Amenorrhea.

Choice A: Chadwick’s sign is a non-specific, early sign of pregnancy that is typically characterized by a bluish discoloration of the cervix, vagina, and vulva. The Chadwick sign can typically be observed as early as six to eight weeks after conception, and commonly disappears shortly after birth. However, it’s not a definitive indication of pregnancy, and the absence of it on physical exam does not exclude a potential pregnancy.

Choice B: Hegar’s sign is a non-specific indication of pregnancy that is characterized by the compressibility and softening of the cervical isthmus (i.e., the portion of the cervix between the uterus and the vaginal portion of the cervix). It typically presents between the fourth and sixth week of pregnancy and may be present until the 12th week of pregnancy. However, the Hegar sign is not a definitive indication of pregnancy, and the absence of it does not exclude a potential pregnancy.

Choice C: A positive pregnancy test By 10 weeks, a home pregnancy test would almost certainly show a positive result if the woman is pregnant. This is because the hormone human chorionic gonadotropin (hCG), which is produced by the placenta after implantation of the embryo into the uterine wall, would be present in high enough levels to be detected by the test. However, a positive pregnancy test is not a presumptive sign of pregnancy, but rather a probable one.

Choice D: Amenorrhea, or the absence of menstrual periods, is often considered the most presumptive sign of pregnancy. This is because it’s one of the first noticeable signs of pregnancy for many women. By 10 weeks of gestation, the woman would likely have missed two menstrual periods if she usually has regular cycles. However, while amenorrhea is a common early sign of pregnancy, it can also be caused by various other conditions or factors such as stress, significant weight loss or gain, or certain medical conditions. Therefore, a missed period should be followed up with a pregnancy test to confirm pregnancy.