The second trimester is normally a quiet time when the generalities of maternal and fetal health and appropriate fetal growth are observed. There are many self-help books on pregnancy, but each visit offers you a chance to add a perspective to the things you are reading. A free exchange of questions and answers addresses those things important to you as a prospective mother, and a caregiver’s particular communicative skills will determine the quality of your education as it pertains to your particular pregnancy. Since this is usually the quietest trimester, it is a good time to ask a lot of questions that apply to your particular pregnancy.
What to Expect
Wondering what to expect from your doctor’s visits this trimester? You’ll meet with your OB-GYN every two to four weeks, depending on your doctor. At each meeting, your healthcare provide will check the following:
- Fundal height
- Fetal heart tones
- Your blood pressure
- Your weight
- Your urine
The Prenatal Record
The prenatal record is a synopsis of your entire pregnancy. It is a record of fields on a grid sheet that can portray sequentially the progressions of fundal heights, blood pressures, weights, urine tests, and documentation of fetal heart tones (FHT). There are also areas in which to record unique notes per visit and any complaints of swelling (edema).
This grid sheet is designed to flow down the page of the prenatal record so your doctor can see with a glimpse any trends worthy of concern. It is easy with this type of notation to see a steady rise in blood pressures or a sudden jump in weight. There are other parts of the record to go into more detail, especially if the necessary documentation warrants it, but this grid is the schematic from which your doctor will “eyeball” your pregnancy each visit. Even the newer electronic medical records endeavor to give the look and the feel of this grid sheet.
The gestational age is recorded as the pregnancy progresses. Just as a downward scan can see any trends during the pregnancy, a scan horizontally will give a snapshot of each whole visit.
Urine Dipstick Tests
Protein and sugar (glucose) spilling in the urine are the most noteworthy items that screen you for the two most famous complications of pregnancy, Pregnancy Induced Hypertension (PIH or preeclampsia) and gestational diabetes (GD). These are usually graded as a 1+ to 4+ scale, or negative. Protein is a bit quirky, and a trace of protein is usually ignored. Higher recordings will prompt a 24-hour urine collection to actually count the amount of protein (a test deemed accurate as compared to this crude dip test).
It’s not hard to get a positive glucose reading from your urine if you were naughty and had two donuts for breakfast. But spilling sugar enough to register on the dipstick is abnormal in the absence of any recent high calorie crimes. Typically, the screen for gestational diabetes is around the beginning of the third trimester, but spilling sugar anytime during the second trimester may prompt an earlier screen in addition to the traditional 26-week glucola test.
A sudden jump beyond which can be explained by diet alone is usually the result of a sudden fluid retention. Fluid is normal to some extent in pregnancy, but when accompanied by blood pressure increases and protein in the urine can be a sign of PIH.
The second trimester has a bit of a sudden weight jump at around 20 weeks. Since delivery involves bleeding at the time, your body will make extra blood (red blood cells and plasma) during the pregnancy. The extra blood helps keep you out of dangerously anemic territory in the postpartum period. During this mid-pregnancy phase, however, the extra blood is disproportionately produced, so at mid-pregnancy a six to eight-pound weight gain between visits is not unusual.
You will probably be very concerned until the extra-blood effect is explained, so take heart. You don’t want to find yourself in a panic, figuring eight pounds every three weeks adding about sixty pounds before it’s all over. Of course, if you gain six pounds every visit, you can only milk this “extra blood” explanation once.
Blood pressure actually falls a little bit during this time. But there’s a self-indulgent menace approaching – the expanding uterus.
As the uterus increases in size, the less its ligaments support it. The ligaments ultimately fail altogether when the uterus is too big to fit in the pelvis. It lifts into the abdomen as an abdominal organ by the beginning of the second trimester. The Inferior Vena Cava, the main vein, which drains the entire body below, the heart, splits above the pelvis, blood flow from both legs merging into the larger blood vessel. This is the same situation with blood from the heart in the aorta, splitting into smaller arteries for each leg. But arteries, and the aorta is the largest, have their own pulsatile force and can stand up fairly well to a weight sitting on top. The flow continues. Unfortunately, veins are weaker – they don’t have the tough muscular shell that arteries do and they don’t pulsate, blasting their load onward. Blood flow through them is more of a negative pressure system flow, drawn up by the vacuum-like process created by the heart pumping it back out, further up.
Because of the difference in the way arteries and veins are constructed, veins are collapsible. The Vena Cava is anchored under the floor of the abdomen, so it can’t move out of the way when an enlarged uterus sits right on top of it, right through the abdominal floor. This decreases the flow back to the heart, which decreases the amount of blood pumped back out of the heart through the aorta, and then your blood pressure can fall.
What I’m talking about is a sizeable weight. This isn’t such a problem in the early second trimester, but by about 22 to 24 weeks, you will start to notice this effect. This is why your doctor will tell you to not sleep flat on your back. Your doctor is afraid that although the hypotension may go unnoticed in your sleep, the decreased blood flow to the uterus under less pressure will decrease nutrition and oxygenation to your baby. This is probably not the disaster it seems; otherwise there would be a lot of disasters about. But the mechanics of the physiology are rock solid and make sense. So do everybody a big favor, including your baby, and don’t do it.
Depending on body shape, this particular effect may not present until the late third trimester. But it’s worse the bigger your baby gets. Ultrasound in late pregnancy, with your lying flat on your back, often is interrupted by feelings of nausea. The cure for this is flipping to one side.
The fundal height is just that – the height of the fundus. You doctor will measure from the top of your pubic bone to the curve of the top of the uterus. It’s generally measured in centimeters, and it’s a measurement, as you might suspect, that will increase as your pregnancy continues toward your due date. The fundal height is generally a diagnostic tool held over from the days before ultrasound, but it is still useful in large clinics where the same patient may not get the same doctor twice in a row for her prenatal visits. In those settings it provides some frame of reference for the continuity of the documentation throughout the pregnancy.
There is no measurement more exact than ultrasound, and even this isn’t perfect. But the fundal height, recorded with each visit, is even more inaccurate. Some obstetricians in private practice who see the same patients over and over (small and solo practices) don’t even record it, but merely record whether the size of the uterus is compatible with the gestational age. A physician who is familiar with her patients will generally know when a baby isn’t growing right during the many visits, and if there is suspicion of a growth restricted baby or an LGA (large for gestational age baby), then the standard of care to sort out any worries is ultrasound – not a fundal height.
But the fundal height is very useful in the larger clinics, because many different doctors will see a patient before the due date. Because there needs to be at least some objective frame of reference among the different doctors, the fundal height is still a good idea. It’s not great, but is easy and free. Ultrasound would make more academic sense, but is prohibitive from a cost standpoint when attempted on every visit. Like no two scales reading the same weight the same, also no two doctors are going to measure the same fundal height exactly the same. But if a different doctor gets a discrepancy that’s wildly different from what was recorded by the previous doctor, then ultrasound is justified. This is not very exact science, but it works remarkably well in the larger clinics.
Relying on fundal height as above must take into account any explainable discrepancies. For instance, a third trimester baby who has “dropped” between the last visit and the current one may show a fundal height less than last visit! The lower baby means the top of the uterus is lower, measuring less from the immovable pubic bone than the previous time. A simple pelvic exam can determine the descent of the baby’s head into the maternal pelvis to explain this. If a baby’s turned sideways, as often occurs in the second trimester, the fundal height can be unusually short for what’s expected, since the greatest dimension then lies across the horizontal. A breech baby, usually sitting up high in the uterus, will yield a larger fundal height. These are all circumstances that can defuse concerns over abnormal fundal heights, so it’s obvious that it wouldn’t be a good idea to revise a due date based on a fundal height. (Then again, the fundal height may be just the thing to provoke investigation leading to a diagnosis of breech.)
Because the weight of your occupied uterus can press on the Vena Cava to obstruct blood flow (drainage) back up to the heart, this obstruction backs up the works. When the fluids of your lower body can’t equilibrate with the fluids in your upper body, the bottom half becomes overhydrated. You see this as swollen ankles. The swelling can also be fairly high up, even involving your wrists, giving you the false carpal tunnel syndrome with tingling of your fingers.
Edema is normal, but it can also accompany pre-eclampsia. But swelling in the absence of hypertension, spilling protein, and jumpy reflexes is merely one of the Middle Miseries of Pregnancy. It can continue and worsen, blossoming into a third trimester misery as well.
FHR (Fetal Heart Rate)
Many people think that a baby’s blood circulation is directly connected to the mother’s circulation. This is a myth. Many think that you can tell the gender of your baby by the count of the fetal heart rate per minute. Another myth.
The very fact that your own heart rate and your baby’s heart rate are different is the proof that they’re not connected. If they were, such opposing pulsatile forces would create a midpoint of turbulence, perhaps creating hemorrhoids for you the size of the wheelbarrow they’d have to be carried in.
On the medical record, these rates are recorded. They typically slow down over the course of the entire record. FHR in the second trimester is usually from around 180 (early) to about 160-ish (later). By term, the FHR will be from 120 to 160. These are very fuzzy ranges and the FHR on the same baby can vary wildly as well, which is why you can’t tell the gender from the FHR.
The FHR during the second trimester, especially before 21 weeks, can be irregular. Just as your baby’s liver needs to mature to prevent jaundice and her lungs need to mature so as to breathe air, so too the electrical pathway of her little heart goes through maturation so as to correctly deliver the pulsations that’ll drive the roughly two and half billion heartbeats after birth. Give or take a few. It’s a quirk of normal maturation, but sometimes ultrasound views of the heart or Doppler audio will reveal a fetal cardiac arrhythmia that is absolutely terrifying. I’ve even seen a 20-week baby’s heart stop cold for a moment, only to restart, the child hopping around like nothing happened. Although a developing baby may truly have a heart condition, fetal echocardiography can document otherwise for reassurance. These babies that give the second trimester cardiac frights almost always go on to have no problems at all.
Reflexes and Other Miscellaneous Recordings on the Prenatal Record
The prenatal record is a very personalized documentation, depending on your doctor. More than likely he has personalized it himself. The American College of Obstetrics and Gynecology has its own recommended record, but doctors for the most part design or choose the type they can most easily work with.
Your doctor may have other fields in the grid for things such as reflexes (hyperactivity of which is one of the signs of pre-eclampsia), nausea (mainly a first trimester occurrence), contractions (to watch for troubling preterm labor patterns), and fetal movement.
Fetal movement (FM) is made unnecessary by recordings of the FHR, but reports of a change in the amount of movement would qualify for a special notation, because your doctor is always on the look-out for decreased fetal movement as a sign of fetal jeopardy. This is different from a change in the type of movement, because as your baby gets bigger, you should expect the discrete kicks and flips to settle into more of a squirming and rotational quality – there’s just less room for acrobatics.