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As the estimated delivery date (EDD) approaches, mothers as well as families are more than excited and expectant. But not all things have fixed timings! Good things make you wait a little longer, and sometimes so does pregnancy. Many women jump their expected dates and it is normal to give birth a week or two after your due date. Below we shall walk you through the basics to help you gain an insight into the various aspect of overdue pregnancy.
How Due Date is Calculated in Pregnancy
Expected date of delivery is usually calculated by one of the following methods:
Calculating the due date or expected date of delivery (EDD) is based on the last menstrual period, to determine the unborn baby’s age. This is done by doing ultrasound scans to see how big he or she is. Ultrasound or the USG applies sound waves that travel towards the baby, and return images that help estimate the body dimensions and organ development to the instrument. This in turn, helps in calculating the gestational age or period of pregnancy.
Generally, the date of the last menstrual period (LMP) is used to calculate the EDD. As the 14th day of mensuration marks the ovulation time, the EDD calculated may overestimate the age by two weeks. This may give an erroneous prediction of the EDD and falsely call it an overdue pregnancy.
When is a Baby Considered to Be Overdue?
Generally, babies are born between the 37th and 40th weeks of gestation. The deliveries during this period are called ‘on term delivery’ or normal pregnancy. Babies who are born before the 37th week are known as preterm or premature babies. When the pregnancy passes 42 weeks, it is known as an overdue pregnancy and the babies born are called post-term babies.
Causes of an Overdue Pregnancy
Why do babies go overdue? While there are several reasons for a baby being overdue, some of which are listed below. It is worthwhile to remember that there is no accurate way to estimate the time of delivery.
The first pregnancy may sometimes be overdue.
2. Prior History
If a mother has had one overdue pregnancy, there are chances that subsequent pregnancies may be overdue pregnancies too.
3. Baby Boy
While there is no scientific reason for this, it has been observed that overdue babies are mostly males. It is believed that this is because baby boys are typically larger and heavier than their female babies.
4. Maternal Obesity
Maternal obesity has been known to delay pregnancy. This is because excess weight may come in the way of a body’s response to labour, and the uterine muscles may not contract as expected in overweight women
5. Inaccurate EDD Calculation
A wrong estimation of the LMP or probably a delayed USG might lead to a mistaken EDD.
6. Position of the Baby
Babies who are in breech position (back or sacral presenting instead of head) may be delivered late.
A family history of overdue pregnancies may be one cause of an overdue pregnancy.
The climate may have an impact on the duration of pregnancy as high barometric pressure tends to induce labour while the opposite is true of low barometric pressure.
Sexually Transmitted Diseases, diseases of the liver and systemic endocrine disorders may result in an overdue pregnancy.
10. Increased Maternal Age
It has been observed that when the maternal age is over 35, the chances of an overdue pregnancy are higher.
11. Maternal Psychological Problems
Mentally challenged, or over apprehensive mothers who have a strong fear of having pregnancy or delivery related complications including miscarriages and stillbirths may have an overdue pregnancy.
12. Placental Causes
Rarely placental causes may be responsible for an overdue pregnancy.
Signs & Symptoms of Overdue Baby
Besides simply calculating the expected due date, a physical examination and laboratory investigations are used to identify an overdue pregnancy. Some of these symptoms include the following:
1. Dropping Abdominal Girth Measures
A reduction in the volume of amniotic fluid is suggested by a drop of 5-10cm of abdominal circumference or a drop of about a kilogram in the mother’s weight. This usually happens a day or so before delivery.
2. Change in Elasticity of the Skin
The skin over the belly which can be seen as tense and elastic returns to normal texture and may be an indication of an overdue pregnancy.
3. Start of Breast Milk Production
The production of breast milk generally begins around the time that the baby is expected to be delivered in a normally timed delivery. The beginning of the production of breastmilk may be an indication that the pregnancy is overdue.
4. Signs of Overdue Pregnancy
A few signs noted by the clinician might hint at an impending overdue pregnancy.
- Uterine cervix immaturity
- Reduced quantity and meconium staining or greenish discoloration of the amniotic fluid
- Forewaters missing
- Premature ageing of the placenta lead to its inadequate functioning
- With time the foetus develops more cranial bones that might pose a problem in normal delivery
What are the Risks of an Overdue Baby
Let us discuss some of the risks that are faced by the woman as well as her child in case of an overdue pregnancy:
1. Risks for a Pregnant Woman
An overdue baby is usually big in size. Delivered normally through the vagina, a big baby may cause delivery complications in the mother. Possible birth injuries include trauma to the perineal muscles, cervical tissue or vaginal apparatus. This may result in excessive blood loss, or urinary problems like infections or retentions. This might cause difficulties in the progress of normal labour. Thus, to prevent complications, many obstetricians prefer an elective C-section for an overdue delivery.
2. Risk for the Baby
Delivering after 42 weeks carries certain risks for the new born baby as well. The mortality rate is nearly of post term babies is nearly double that of term babies. Here are some of the possible complications that the baby may face:
- Foetal macrosomia: Post term babies may be born with a birth weight of more than 4.5kgs. This may lead to birth time injuries, including lacerations, excess blood loss, and metabolic complications in the baby.
- Placental insufficiency: With increasing lapse of time after the due date, the placental function reduces, and as a result, the oxygen and nutrient supply to the foetus is also hampered. This may affect the health of the baby.
- Permanent neurological damage or cerebral palsy: The risk of cerebral palsy increases after the due date. While there is no definitive proof for this, one explanation is that the brain becomes vulnerable to damage as the baby becomes overdue.
- Meconium aspiration: An over dated baby usually passes stool in the amniotic fluid called meconium. There are chances that the baby might breathe this meconium leading to respiratory complications like infections.
- Delayed or stunted growth: As the baby grows larger, it runs out of room in the uterus and stunts its growth.
- Reduced amniotic fluid: Amniotic fluid reduces after 42 weeks of pregnancy which can lead to issues like poor functioning of the placenta.
- Foetal distress: Baby might be in distress, cardiac or respiratory. This can happen when the baby’s growth gets stunted.
- Stillbirth: The placenta begins to lose its efficiency due to reduced amniotic fluid. This is turn causes issues for the baby as it has trouble in getting all its nutrients and oxygen which may lead to a stillbirth.
Tips to Survive an Overdue Pregnancy
What Can Doctors Do?
Your doctor will perform an analysis after 42 weeks or pregnancy (about twice a week). This is a cervical examination to see whether it has thinned and widened (dilated) to prepare for labour. Your baby may be monitored by one of the following methods:
1. Non-stress Test (NST) or Cardiotopograph (CTG)
The heart rate of the baby is estimated to check the health of the baby.
2. Monitoring the Biophysical Profile
A biophysical profile is more reliable than a non-stress test. In this test, an ultra-sound scan is done and certain physical features are noted such as:
- Baby’s movements
- Amniotic fluid
- Baby’s muscle tone
- Baby’s Respiratory activity
3. Amniotic Fluid Index or AFI
An ultrasound helps determine the quantity of amniotic fluid which in turn confirms the adequate functioning of the placenta.
What Can a Pregnant Woman Do?
It is a common dilemma among expecting mothers when they ask themselves “What to do when baby is overdue?” Counting the foetal movements is a simple way to know if the child is healthy. When the due date is passed, the infant should be monitored closely. A healthy baby often moves frequently whereas a baby that is sick tends to be less active.
Inducing Labour in Post Term Pregnancy
It should be a matter of concern when pregnancy continues without the signs of labour for more than ten days. The methods of Inducing labour medically include:
1. Digital Membrane Breech
Following a brief vaginal examination, the obstetrician may use a sterile digit or finger to manipulate the cervix to make a breech in the water bags to induce labour.
2. Prostaglandin Gel Local Application
Prostaglandin is a natural substance in the body and helps the uterus to contract during labour. It is locally applied in the vaginal canal and it aids in cervical softening that permits rapid and natural progression of labour.
3. Intravenous Pitocin Infusion
Intravenously infusing the drug Pitocin is a common method implemented to induce labour. Pitocin is a synthetic analogue of oxytocin, the chief hormone responsible for uterine contractions and later breast milk production.
How to Avoid Overdue Pregnancy
Medical science doesn’t have tools to predict one’s delivery time accurately, as each woman and her pregnancy may have a different course of nature. While certain food items like castor oil should be avoided as it makes contractions more painful, here are a few approaches that can be used to stimulate labour:
1. Having Intimate Sexual Contact
It is said that having an orgasm may cause oxytocin release, for example after nipple stimulation. It is this hormone oxytocin that is responsible for uterine contraction. Semen has certain amounts of prostaglandins, which helps soften the cervix.
2. Acupuncture (under supervision)
Studies have shown that acupuncture increases the readiness of the cervix to go into labour.
3. Homeopathic Remedies (under supervision)
One can try out homeopathic medicines such as pulsatilla and caulophyllum to induce labour.
4. Herbal Preparations (under supervision)
Many herbal remedies are known to help stimulate labour such as black cohosh and Lobelia. However, improper use can lead to an overdose which is why one should consult a medical professional before consuming them.
5. Regular Walks
Walking has been known to release oxytocin that helps in starting contractions.
6. Having Hot Foods
It is probably related to the theory of adrenaline and its effects on muscle contractions. However, there is no scientific evidence to back this claim though numerous people swear by this method.
Pregnancy and labour are crucial milestones in every woman’s life. Especially towards the end of pregnancy, waiting for labour to begin can make you apprehensive. First time mothers are overtly anxious, worried and sometimes depressed. A safe pregnancy, an uneventful delivery and a healthy baby are every woman’s desire. Remember that your mental strength, patience and awareness make all the difference. It is a matter of fact that most overdue babies are born healthy. Besides, with the advancement of medical and surgical techniques, overdue pregnancies can be timely diagnosed, efficiently planned and managed electively.