Childbirth~ that incredible human occurrence that causes joy and fear, avoidance and intrigue. A woman’s body is uniquely designed to conceive, nourish and bring forth another human life. But does Mother Nature need help? That MUCH help that an estimated 20% of US women are induced yearly?1 This rate is important. Since 1982, the American College of Obstetricians and Gynecologists (ACOG) have had specific guidelines in place that recommend against elective inductions in early term or before 39 weeks 5. Similarly, the Association of Womens Health, Obstetrics and Neonatal Nursing (AWHONN) plus the March of Dimes have campaigns to make the public aware that babies should be growing inside the Mother’s uterus for as long as possible.
So how long is a pregnancy?
If you count nine months and each month has 4 weeks, you count 36 weeks through simple math. However, estimating gestational age is not that easy. Called Naegele’s Rule, the expected date of delivery (EDD) is calculated by adding one year, subtracting three months, and adding seven days to the first day of a woman's last menstrual period (LMP). The result is approximately 280 days (40 weeks) from the LMP. And the EDD or Due Date is an ESTIMATE. Each woman with each pregnancy gestates their babies differently with approximate variation of up to five weeks.2
How does labor begin?
hCG: The early chorionic villi of the implanted ovum secrete human chorionic gonadotropin (hCG), which prolongs the life of the corpus luteum. The result is the continued production of estrogen and progesterone, which are necessary to maintain the endometrium. During pregnancy, hCG appears in maternal blood and is excreted in the mother's urine, allowing diagnosis of pregnancy by tests.
hPL: The chorionic cells of the placenta produce another hormone, human chorionic somatomammotropin which is also known as human placental lactogen (hPL). This hormone influences somatic cell growth of the fetus and facilitates preparation of the breasts for lactation.
The increase in hCG and hPL in the mother is thought to be responsible for many important changes during pregnancy such as growth of the uterus and the development of the breast duct system. Estrogen is also helpful in breast duct system development and progesterone is valuable in the development of the lobule-alveolar system.
The pituitary gland enlarges during pregnancy and is the source of production of oxytocin. The posterior lobe is the primary source of oxytocin, which has a stimulating effect on the uterine muscle and lactation.
The adrenal cortex increases in activity during pregnancy. The secretion of cortisol by the adrenals does not change yet the metabolism of cortisol is changed as a result of estrogen. There is an increase in aldosterone production by the adrenal glands and this hormone results in the decreased ability of the kidneys to handle salt during pregnancy. This leads to some fluid retention or edema.
Relaxin is produced by the ovaries and is primarily responsible for softening ligaments and cartilage. The softening of cartilage, especially in late pregnancy, is the cause of suprapubic discomfort, waddling, and the ability of the pelvis to spread during the birth process.
What happens when induction happens too soon?
For Babies: Organs such as brain, lungs and liver need ample time to develop ~ up to 39/40 weeks! Babies born at 39+ weeks are less likely to have vision or hearing problems, have an easier time staying warm and can suck/swallow and eat better.6
For Mothers: induction of labor causes contractions that are characteristically harder, stronger and closer together than the normal progression of labor, making labor more difficult with which to cope. There are higher risks of infection and uterine tears/rupture. Inductions may not work if there are not sufficient oxytocin receptor sites on the uterus. Oxytocin receptor sites are developed through the pregnancy and are necessary to receive the oxytocin that the body produces. If there are insufficient oxytocin receptor sites, neither mother’s naturally-produced oxytocin nor the artificial oxytocin or Pitocin, will take effect. Thus, with a “failed induction” a cesarean section occurs.3,6
AWHONN has a list of reasons – 40 of them – as to why a pregnancy should go the full 40 weeks. You can access and print the pdf article for distribution by clicking here.
Diligence must be exercised when monitoring labor and fetal well-being. Hofbauer, the first to use oxytocin to induce labor, said in 1927 that oxytocin, "with its power of producing regular, rhythmical and forcible uterine contractions, should be regarded as a most beneficent and valuable agent, which, however, should always be employed with care and a realisation of its limitations and dangers." His words remain valid today.4
3. Smith, L. (2012) Impact of Birthing Practices on Breastfeeding (2nd Edition).
4. Diligence Shyken, J.M. et al. (1995) Oxytocin to induce labor. Clinical Obstetrics and Gynecology. June, 38(2):232-45.
5. ACOG https://www.acog.org/About_ACOG/ACOG_Departments/Deliveries_Before_39_Weeks