I’ve read a couple of novels recently that took fiction to a whole new level with regard to pregnancy and delivery. In one, a “neonatal nurse” flipped a breach baby during delivery, in another, a 6-week pregnant woman had an audible fetal heart rate, a traditional abdominal ultrasound, and had difficulty with her pants becoming tight and her bra no longer fitting. So I thought perhaps some ground rules were in order…
First, pregnancy is caused by…yeah, I’m skipping this part. One of my romance-writer friends can fill that in. But…I will say that the youngest pregnant patient I’ve cared for was 12 years old, though hers was not consensual sex. Anyone through puberty has the capability to become pregnant/cause pregnancy.
Pregnancy is logged in weeks from the last menstrual period, with 40 weeks being “fully cooked.” In fact, most women become pregnant mid-cycle, so they are only pregnant for 38 weeks. During those first few weeks of pregnancy, lots happens to the mother-to-be. She may feel out of breath as her brain resets the target amount of carbon dioxide in her body. Her breasts begin to grow, slowly. She feels exhausted, maybe emotional, nauseous (man, what we put up with for our kids!).
At this point, the only way to really assess the baby is with a trans-vaginal ultrasound – a probe advanced to the cervix, with which an image of the lima bean is visible. A single pixel blinks on and off…that’s the heartbeat, and it’s visible at about 5 weeks, but it can’t be heard quite yet.
The first trimester (approximately 13 weeks) is the worst for nausea, and the most
important for fetal development and avoidance of exposure to drugs and chemicals. With an ultrasound probe pressed hard against the lower abdomen, the heart beat can first be heard around 12 weeks. So if you want the mom and dad to smile lovingly at each other at the sound of their baby’s heart…make sure she’s at least that far along.
The second trimester is when things become apparent to others. First-time moms feel the baby move for the first time (“quickening”) around 18-20 weeks. Repeat moms recognize the fluttering a little earlier. The baby bump starts to appear (different from just over-eating and becoming overweight). The height of the fundus (top of the uterus, measured from the pubis) in centimeters, should be about the same as the number of weeks pregnant (assuming a single baby). Healthy moms visit their ob about every 4-6 weeks at this point, with and ultrasound around 16 weeks to look for major structural problems in the fetus.
Viability (where the baby has a chance to survive outside the womb) occurs between 23 and 24 weeks, so just over half-baked, but these babies require major resuscitation and advanced care. If your character is delivering a 24-week baby in the woods, it won’t survive. Most babies achieve lung maturity around 34 weeks, so that’s about the age a baby born in the woods could very reasonably survive.
Since 2000, we almost never deliver breech babies vaginally, unless it’s the 2nd twin. We might try to flip a breech baby before labor, but the success rate isn’t great, and there can be complications.
Unless there are problems, like high blood pressure, diabetes, a huge baby, etc, we don’t induce labor or perform an elective Cesarean until 39 weeks gestation. This is also relatively new. Turns out baby lungs do better if we wait those extra few days. In fact, if we do an elective Cesarean at 36 weeks and 6 days our obstetricians have to defend the move…as if we know with certainty the exact day the baby was conceived. Rarely do we allow a woman to go past 41 weeks either.
Lots more info about pregnancy and delivery. Bring on the questions!