Placenta Previa is a condition where the placenta embeds itself in such a way that it partially or completely covers the cervix. In such a case, the placenta lies low in the uterus and is at risk of separation from the uterine wall during labor contractions. When a pregnant woman experiences painless vaginal bleeding during the third trimester, the doctor may conduct an ultrasound to check for placenta previa. Other symptoms that might indicate placenta previa are a large uterine size, breech or transverse position of the baby or premature contractions.
Usually placenta previa is detected during routine ultrasound scans of the growing fetus. Women who are over 35 years or have had multiple pregnancies are at higher risk of placenta previa. If a woman is diagnosed with placenta previa, she will need to take bed rest. Often hospitalization is necessary. Travel must be avoided and pelvic examination by the doctor is not advisable. Instead the doctor will resort to ultrasounds and MRI.
Placenta previa can cause growth retardation in the fetus due to irregularly placed placenta. This can lead to increased chances of congenital anomalies. The expectant mother is at risk for hemorrhage. Blood transfusion is resorted to in cases of severe bleeding.
A baby who is born without any signs of life at or after 24 weeks of pregnancy is defined as still birth. It could have been during late pregnancy, called intrauterine death or could have died during labor or birth, called intrapartum death. Though stillbirth is uncommon, it cannot be said as rare.
Genetic factors or
How the placenta works or
Age and lifestyle of the parent and
Out of these, problem with the placenta or placental insufficiency is probably the most common cause of a baby dying in the womb. Though the exact reason for placenta not functioning properly is not understood, the blood vessels that connect a mother to her baby could become constricted. This may result in a drop in nutrients and oxygen to the baby, causing growth problems and hence death.
Reduced blood flow to the baby via the placenta could be due to pregnancy illness called Preeclampsia.
About 10 % of the babies are still born due to genetic or chromosomal defects. This happens when the placenta separates from the womb causing placental abruption.
Sometimes health condition of the mother such as diabetes, and rare infections such as flu, group B streptococcus, listeriosis or toxoplasmosis can cause the loss of baby in the womb.
The risk of stillbirth is more in older women. This risk appears to be highest at around 41 weeks. That is why in some hospitals, an older mother-to-be is sometimes recommended to have labor induced few weeks before due date. It is very rare that a baby may be stillborn at the very end of pregnancy. This could be due to problems with the placenta wearing out. If you are several weeks past the due date, the placenta may not work as well as it did earlier. Hence, induced labor is recommended by about 41 weeks. Lifestyle factors such as obesity, heavy drinking and smoking in pregnancy increase the risk of a baby being stillborn. Smoking again, can restrict a baby's growth as it reduces the supply of oxygen to the baby via the placenta.
Stillborn during labor or birth
It is quite rare for a baby to die unexpectedly during labor or birth. Most of the times, stillborn babies are lost when they are still in the womb. If the baby is large, in rare instances, his/her shoulders may get stuck as he/she leaves the birth canal, severely reducing the flow of oxygen to the baby. While most babies recover well, sometimes the shoulder dystocia can result in a baby being stillborn. Another cause is problems in the umbilical cord which could result in loss of oxygen to the baby. Either the cord can slip through the cervix or becomes wrapped around a baby's neck.
Fetal behavior and changes in fetal movements or sleep-wake cycles can indicate if there is any fetal distress. Decreased or cessation of fetal activity is an indication of fetal distress or even death. Medical examination including a non-stress test is recommended. Obstetricians recommend the use of a kick chart to assist in detecting any changes. Fetoscopy/doptone, ultrasound or electronic fetal monitoring aid in confirming fetal distress or death. In case the fetus is alive but inactive, extra attention is given to the placenta, and umbilical cord during ultrasound examination to ensure that there is no dearth of oxygen supply and nutrients to the baby.
What happens if the baby dies in the womb ?
The sad reality is that even after the baby dies, the mother has to go through with the birth, as it is better for her health and physical recovery. It is rare for a stillborn baby to be born by cesarean section. In most cases, the labor will have to be started artificially induced. While some parents would want to have the induction as soon as possible, some others would prefer to wait a day to two to see what happens if the labor starts by itself. In case the mother is infected, they will advise the labor induced straightway.
Whether induced or natural labor, the midwife or doctor will administer effective morphine-based pain relief. In case of twins or more, and the death of one baby occurs, the doctor normally advises not to have an induction of labor. Other issues such as whether or not the babies share a placenta, and at what stage the loss occurred should be viewed. The doctor would give the best shot for the live baby or babies to develop and mature a bit longer in the womb. The babies can then be born at the same time, when it is best for the mother's health.
A post mortem examination is done to:
1. Identify a cause or causes for death
2. Provide information about the baby's development
3. Information about health problems to combat future pregnancy.
4. Officially confirm the baby's gender.
Not all parents agree to get a post mortem done and it is only carried out with prior written consent of the parents. Post mortem could also be refused for personal, religious or cultural reasons or for any other personal reasons which the parents may not want to disclose.
Implications for next pregnancy
The decision to try for another baby can be difficult for some mothers, whereas, there is an overwhelming urge to get pregnant again as soon as possible in some others. Depending upon the cause of the stillbirth, the doctor should be able to work together to reduce the risk of it happening again.
Chorionic Villus Sampling
The diagnostic procedure of taking out a sample tissue (Choroinic Villi) from the placenta to detect congenital abnormalities in a fetus is known as Chorionic Villus Sampling (CVS). With the guidance of ultrasound, the position of placenta is first determined. There are two methods - trans-cervical and trans-abdominal to perform this test. The position of the placenta helps the physician choose a suitable method. For trans-cervical CVS, parameters like the position of the uterus, the size of the gestational sac and the position of the placenta inside the uterus are first determined using abdominal ultrasound. Using a good antiseptic, the vulva, vagina and the cervix are cleansed. The abdomen is also cleansed for trans-abdominal procedure.
Trans cervical procedure: A thin plastic tube is inserted through the vagina and cervix for the trans-cervical procedure to reach the placenta. A tiny sample of chorionic villus tissue is taken out after locating the exact position of the placenta.
Trans-abdominal procedure: This procedure is similar to the earlier one, but a needle is inserted through the abdomen in this test to reach the uterus and then to the placenta. The chorionic villus sample tissue is drawn into the syringe, while the needle is guided by ultrasound.
This sample is then taken to the laboratory for evaluation. This procedure can be conducted even earlier than amniocentesis to detect any congenital defects present in the fetus. It is done at around 10 to 12 weeks after the last menstruation. Study of the DNA, chromosomes and enzymes of the fetus can be conducted using the sample taken out during the test. Results are available within a week or two. If there are any abnormalities found in the fetus, it is easy to conduct a therapeutic abortion, in case it is necessary. Pregnant women over the age of 35 who are at risk for giving birth to a baby with Downs Syndrome or those who have had birth defects in an earlier pregnancy are advised this test. For detecting neural tube defects and the Rh-incompatibility, amniocentesis is a better option. Hemoglobinopathies and Tay-Sachs disease can be detected through Chorionic Villus Sampling.
The risk involved in using CVS is slightly higher when compared to amniocentesis. Some complications like rupture of the amniotic membrane, miscarriage, infection, bleeding, Rh-incompatibility in the mother if she is Rh-negative and contamination of the sample with maternal cells can occur. When CVS is performed after 10 weeks of gestational period, there is a risk for limb defects in the fetus. If the mother's blood is Rh-negative, she has to receive Rho GAM to avoid Rh incompatibility. After the CVS, it is advised to have an ultrasound done after about two or four days to ensure the fetus is fine.
Bibliography / Reference
Collection of Pages - Last revised Date: March 21, 2019