Getting enough iron prevents anemia, which is linked to preterm birth and low-birth weight babies.

Your hands or feet swell suddenly or you rapidly gain weight — it may be preeclampsia.

Since your body temperature rises after you release an egg (ovulation), if you chart your temperature, it can tell you when you’re most fertile.

The most common genetic causes of infertility are chromosomal conditions that affect sperm production. These include: Klinefelter’s syndrome, Y chromosome deletions, other genetic problems, such as Down syndrome.

The risk of high blood pressure during pregnancy is about double for women over 35 compared with younger ones; hypertension affects about 10 to 20 percent of pregnant women in this age group. Gestational diabetes is two to three times more common in women over age 35 than in younger women, and recent studies show the risk is even higher if the woman has gained weight over the years. Age 35 to 39 is also when women are most likely to have twins.

If you have missed a pill and are worried, you will need to take emergency contraception.