Women's Healthcare Topics
James Brann, MD. Ob/Gyn

28 Weeks Pregnant

Pregnant Belly Changes

Congratulations! At 28 weeks pregnant, you are into your third and final trimester of pregnancy.

Currently, your uterus measures at least 3 inches above your naval and the fundal height (measurement from the top of the pubic bone to the top of the uterus) is roughly 28 centimeters long.

As you get larger in your pregnancy, you may notice that you are having a hard time breathing, or feeling a little short of breath. This is a common pregnancy symptom, caused by your growing uterus compressing your diaphragm. You're more likely to feel short of breath during pregnancy if you are carrying your baby high or if you are pregnant with twins or multiples.

Though shortness of breath is a bothersome sensation now, you will get relief in the final weeks of your pregnancy, when your baby drops into your pelvis (this is called "lightening").

You may want to start counting your baby's kicks. Although it's not medically necessary for you to count fetal kicks (unless your midwife or doctor has advised you to), it's a good way to feel more secure in knowing your baby is healthy.

The following are three ways to do baby kick counts that indicate the baby is doing well:

  • At least 10 movements during 12 hours of normal maternal activity

  • At least 10 movements over two hours when you are at rest and focused on counting

  • At least 4 movements in one hour when you are at rest and focused on counting

As you approach your third trimester of your pregnancy, you will have more frequent prenatal appointments. Instead of seeing your doctor every four weeks, like you have been doing up until 28 weeks pregnant, you will have prenatal visits every two weeks until the 36th week and every week thereafter.

You are probably huge right now. Your pregnancy weight gain at 28 weeks pregnant is around 20 or 21 pounds. Can you believe it? Twenty one pounds! That's like carrying a very heavy watermelon in your stomach. No wonder you are plagued with back pain in the second and third trimesters!

By the time that your baby is ready to be born, you may have gained anywhere between 25 and 35 pounds for an average sized woman. Overweight women should only gain between 15 and 25 pounds, and underweight women should aim to gain between 28 and 40 pounds.

Pregnancy Health Section

Preventing Rh Sensitization during Pregnancy

Early in your pregnancy, you had your blood tested to see if your blood has the Rh factor (a protein found in red blood cells). If you do have the Rh factor, you are Rh positive. If your blood lacks this protein, you are Rh negative. (Most people are Rh positive). In some cases, this blood test (called an antibody screen) occurs in your second trimester, when you have the glucose-screening test for gestational diabetes.

If you are Rh-negative and your partner is also Rh-negative, this doesn't pose a problem during pregnancy. However, in most cases, you won't know what your partner's Rh factor is. If your partner is Rh-positive and you are Rh-negative, this means that your baby has a possibility of being Rh-positive.

RH Sensitization in Pregnancy Rh-negative pregnant women face the risk of Rh sensitization - a pregnancy complication that occurs when your Rh-negative blood comes into contact with your baby's Rh-positive blood and your blood produces antibodies that attack your baby's blood. This can cause anemia in your unborn baby, leading to brain damage, fetal death, and serious illness in your little one.

For first pregnancies, your baby will be born before your body develops enough antibodies to cause your little one any harm. However, once you have these antibodies in your system, they have the potential to harm future pregnancies.

How to Prevent Rh Sensitization To prevent Rh sensitization, you will get an injection of Rh immune globulin (brand name: RhoGam) at 28 weeks pregnant. This will prevent your body from producing these harmful antibodies in your last trimester.

If your body is already producing these antibodies at this point in your pregnancy, you will not receive this injection. Instead, your baby will be monitored closely.

After your baby's birth, if your baby is Rh positive, you will receive another injection of RhoGam to prevent these antibodies from forming. If your baby is born Rh negative, you will not receive another shot, since you have no risk of developing the antibodies.

Fetal Growth Restriction or Intrauterine Growth Restriction

Fetal growth restriction (FGR), also called intrauterine growth restriction (IUGR), is the term used for a baby whose weight is below the 10th percentile for gestational age.

It is important for your doctor to determine whether your baby is healthy and just small or is at risk for developing fetal growth restriction that can cause problems for your baby during pregnancy.

Common Causes for Fetal Growth Restriction Include:

  • Genetic factors and chromosomal abnormalities

  • Multiple pregnancy

  • Infections that developed earlier in your pregnancy (such as rubella, toxoplasmosis, cytomegalovirus, herpes, malaria, etc.)

  • Placenta abnormalities

  • Nutritional deficiencies in the mother, or poor weight gain during pregnancy

  • Hypoxemia (low blood oxygen)

  • Blood disorders (such as sick cell diseases) and autoimmune disorders

  • Substance abuse and cigarette smoking

  • Pregnancy through assisted reproductive technologies (such as IVF fertilization)

How your Doctor Identifies Fetal Growth Restriction?

Symphysis-fundal height measurement — By measuring the distance between the top of the pubic symphysis bone and the top of the uterus with a measuring tape your doctor can get an idea if your baby is growing poorly. A fundal height measurement in centimeters that is at least three centimeters below what is expected for your baby’s gestational age is suspicious for Fetal Growth Restriction.

Ultrasound Diagnosis — If your doctor has a suspicion that your baby has Fetal Growth Restriction an ultrasound will be performed to try to confirm or exclude the diagnosis.

Typically, ultrasound exams in pregnancy are routinely performed at the 16 to 20 weeks to establish gestational age and identify any problems. Then repeated at 32 to 34 weeks to evaluate fetal growth. Ultrasound estimation of your baby’s weight is the best way to screen for and diagnose Fetal Growth Restriction.

If your baby has Fetal Growth Restriction your physician will perform the following:

Initial Assessment
  • A detailed ultrasound of your baby’s body is recommended in all cases of fetal growth restriction to look for major congenital anomalies.

  • If a major congenital anomaly is found, then you will undergo genetic chromosome testing (amniocentesis).

  • Infections that developed earlier in your pregnancy (such as rubella, toxoplasmosis, cytomegalovirus, herpes, malaria, etc.)

  • Maternal blood tests will be performed to look for evidence of current viral infections.

Prenatal Visits
  • Serial ultrasound for baby’s growth, baby’s behavior (BPP), amount of amniotic fluid, and blood flow in the umbilical cord vessels will be done to monitor baby’s well-being (one to seven times per week) or baby’s growth (every two to four weeks).
  • Timing of delivery is determined by both gestational age and fetal condition.

  • If a baby is preterm (“remote from term”), with evidence of a normal umbilical artery blood flow will be monitored and no delivery is planned.

  • Immediately deliver is indicated for any pregnancy that is ≥32 weeks with abnormal umbilical artery blood flow.

  • If your baby is term or late preterm, delivered is indicated if there is evidence of maternal hypertension, failure of apparent growth over a two- to four-week interval, the biophysical profile score is low (less than 6), and/or umbilical arterial blood flow is abnormal.

Labor and a vaginal delivery is a reasonable approach, no C-section is indicated. During labor, continuous fetal monitoring is recommended to look for non-reassuring fetal heart rate patterns that suggests the baby is in stress. Your doctor will be prepared for rapid intervention if there is any evidence your baby is in trouble.

Baby Section

Growth and Development of Baby

At 28 weeks pregnant, your baby now weighs over 2 pounds and measures around 14.8 inches from head to toe! (Remember there is variability between different babies at this stage of fetal development. Some babies will be larger; others smaller.)

Between pregnancy week 28 and 29, the growth of twins and multiples will slow down, when compared to single babies, due to the limited space in their womb. However, twins and multiples will still move around and kick as much as they can.

Between 28 weeks pregnant and 32 weeks, the level of amniotic fluid in your womb will reach its maximum amount. After 32 weeks, the amount will remain constant until your baby is full term, when the level starts to decrease.

Your baby's hair is growing longer, and his or her beautiful eyelashes and eyebrows are also growing longer and thicker.

Many babies will move into the head-down position by now (the best position for an easier labor and delivery). However, it's possible that these babies will continue doing somersaults for the next few weeks until they settle into their actual labor and delivery position.

Your baby is practicing breathing movements and your baby's lungs are filled with amniotic fluid at this stage in your pregnancy. Up until this week, your baby's breathing movements have been random. But now they are starting to reflect your baby's sleep-wake patterns.

Your baby's yawning patterns are more developed. Instead of an occasional yawn, yawns occur in succession, one after another in a repetitive pattern. (next week)


Doctor's Corner

Pregnancy Week by Week - Women's Healthcare Topics