Term limits

I remember the moment that I knew that I was pregnant with my second child.  I had gotten home from a shift at the hospital and was feeling both nauseous and hungry at the same time.  (In hindsight, that should have been a tip-off all by itself...)  I opened the refrigerator and found a Happy Meal bag with leftover chicken nuggets on the bottom shelf, the leftovers from a trip my 2 1/2 year old son had to McDonald's with Grandma.  I actually sat down on the linoleum floor in front of the open refrigerator and ravenously devoured every remaining cold, stale chicken nugget, even the ones that my son had taken a small bite out of.  Somewhere between chicken nugget number two and three, the light bulb went off.  A home pregnancy test confirmed what I already knew, and I adjusted my life plan to prepare for pregnancy number two.

For many women that "ah-ha" moment shifts us from "me" mode to "we" mode.  Decisions about health, travel, work, and relationships are made in the context of the pregnancy.  We think and act both consciously and subconsciously in ways that will protect us and our unborn child. We consider our "due date" as the inflection point between life as we now know it and the next phase of life that includes our baby.

Due dates, however, are nebulous things.  A birth plus or minus a couple of weeks of the due date is be considered "term", and the vast majority of these babies are healthy.  An infant is born prior to 37 weeks, though, is considered to be premature.  These babies require special attention, and depending on the degree of prematurity, can have prolonged hospital stays after delivery. Clearly, the best thing for babies is to stay in the womb until term. So, keeping that in mind, are there things that expectant moms can do to increase the likelihood of carrying a pregnancy to term?  In the broadest sense the answer to that question is yes, but warrants a discussion of the factors that are associated with prematurity.  Like many other things in life, some are within our control and some are not.

Perhaps an oversimplification, but I generally think of premature birth as resulting from a situation in which the environment that the infant is in somehow is no longer favorable. Sometimes this can be due to something abnormal with the uterus itself, sometimes due to a medical condition or illness in the mother, and sometimes due to a condition with the infant.  For the sake of discussion, we can break this down to three categories:  The Uterus, The Mom, and The Baby. The following is by no means a comprehensive review, but should give a general idea of the role each has in pregnancy and some conditions which can affect pregnancy outcome.

The Uterus:

The uterus is truly an amazing structure.  In the non-pregnant women it is about the size of a plum.  By the sixth week of pregnancy it is the size of a small orange.  Fast-forward to the midway point of pregnancy at 20 weeks, and the top of the uterus can be felt at the level of the belly button. It serves multiple functions throughout the pregnancy.  It protects the developing infant in a microenvironment that adjusts to changes in the size of the baby.  It is the conduit of nutrition to the infant at its interface with the placenta.  Ultimately it somehow senses when to start the process of labor and begin the series of contractions that result in birth.  Conditions that adversely effect the normal growth of the uterus during pregnancy can adversely effect the pregnancy.  Examples include structural problems such as a bicornuate or unicornuate uterus, or large uterine fibroids which effectively reduce the size of the uterine cavity, and polyhydramnios in which there is excessive amniotic fluid production and the uterus expands beyond the expected size for a given gestation.  These conditions can be restrictive to the continued growth of the fetus and/or can bring about uterine muscle irritability and the onset of labor.

When considering the ability of the uterus to remain pregnant until term, it is also important to assess the cervix.  The cervix is the opening of the uterus which ideally remains closed until the onset of labor at term.  When the cervix begins to shorten and thin out prior to term it is referred to as being "incompetent".  Although there often is no known cause for this, it can be associated with prior surgery to the cervix (e.g. a cone biopsy), trauma to the cervix (as with therapeutic abortion or previous difficult delivery), and anatomic abnormalities (such as those caused by exposure to DES).  Incompetent cervix is thought to be responsible for up to 25% of midtrimester pregnancy loss.

The Mom:

The bottom line here is to know your own medical history.  Preexisting as well as acquired medical conditions in the mother can have a significant impact on the pregnancy.  As much as we think of the uterus as the "house" of the developing fetus, the mom is the source of the "utilities".  A healthy mom provides a nice, rich blood supply to the infant via the placenta. That blood supply provides the baby with nutrients and oxygen, as well as carries away any waste products of metabolism which the fetus cannot process itself. When you go to your first prenatal visit, your care provider will no doubt ask many questions about things in your medical history that could affect you and your baby's health during the pregnancy. This is, in part, to assess early in the pregnancy risk for preterm birth. Specific topics include infection (for example, bacterial vaginosis, urinary tract infection, sexually transmitted diseases), use of prescription medications, recreational drug use, domestic abuse, and conditions that can cause insufficient blood flow to the uterus such as high blood pressure, diabetes requiring treatment with insulin, autoimmune disease such as lupus, and cigarette smoking. Regular prenatal visits monitor both the health of the mother and the growth of the fetus. Early detection of problems in the pregnancy can prevent minor issues from becoming major ones.

I'd also like to emphasize that pregnancy is a time for expectant mothers to be proactive about their health.  This means changing some lifestyle habits that might be harmful to the fetus.  I have already mentioned cigarette smoking as a concern, and I strongly encourage expectant women (and everyone else for that matter) to take active measures to quit.  Let's not forget our mother's advice to get plenty of rest.  Fatigue and stress are known to negatively influence pregnancy outcome.  A relative newcomer to the list of things to be proactive about in pregnancy is dental hygiene. A series of studies in the past few years have correlated poor oral hygiene and gum disease with preterm labor.  So, add a trip to your dentist on the list of things to do.

The Baby:

Premature onset of labor can result if a baby is not thriving inside the womb.  As outlined above, this can be secondary to things outside the infant, such as an abnormally shaped uterus, compromised blood flow to the uterus or infection in the mother,  but sometimes a primary problem with the developing fetus can be responsible.  Some examples include things like abnormalities in the baby's chromosomes which can impair normal growth, conditions in the infant that result in excess amniotic fluid (polyhydramnios) and over-stretching of the uterus, and twin or multiple gestation which also causes excessive stretching of the uterus. These conditions are often not apparent until the second trimester, so I will again emphasize the need for going to the recommended prenatal visits so the growth of the baby can be monitored.

What if...

What if you think you might be going into preterm labor?  Early recognition of the signs and symptoms of preterm labor can help prevent a preterm birth.  Contact your doctor if you think you are experiencing any of the following:

• Contractions of your uterus at regular intervals.  If they are occurring at intervals less than 10 minutes apart, notify your doctor immediately.
• Persistent low, dull backache
• Pelvic pressure
• Vaginal spotting or bleeding
• Watery vaginal discharge. The may be amniotic fluid and could mean your membranes are ruptured.

Putting it all together:

Let's get back to the question I posed a little earlier:  Are there things that moms can do to increase the likelihood of carrying a pregnancy to term?  Yes, by taking an active role in prevention.  The way to do this is attending regular prenatal exams to make sure that the health of both mom and baby are optimal throughout the pregnancy. Make sure to know your own medical history and relay it to your provider. Be honest about everything in your medical history, including things like drug use and past pregnancies and/or abortions.  Identify situations in your life that are potentially harmful or stressful and take steps to change them.  If you can't do this on your own, ask for help. Take measures to stay healthy by eating healthy foods, sleeping well, and to the extent you can, avoiding catching colds or the flu. (The flu shot is recommended for pregnant women.) Educate yourself about the signs and symptoms of preterm labor.

And finally, share the joy of your pregnancy. Shared joys are doubled.