We’ll define the first month as the six weeks following your last menstrual period, since conception occurs about two weeks into that time. What happens at the microscopic level is indeed profound, including the processes by which egg and sperm unite and there is a combining of DNA to create a new and unique individual. Almost immediately, the conception begins to produce HCG, a hormone crucial to the pregnancy. HCG triggers the ovaries to release large amounts of estrogen and progesterone, which, in turn, cause the lining of the uterus to thicken to provide nutrition to the developing embryo.
Shortly after a missed menstrual period, there are high enough hormone levels to cause the symptoms that alert you something unusual is happening. Breast soreness is most common, followed closely by frequent urination, fatigue and nausea. The majority of pregnancy tests available will turn positive by just three to four days after an expected period is late. There are, however, almost no physical changes that would be noticeable by your physician, so there’s no reason to seek medical care at this stage unless you suspect a problem. It’s best to schedule an office visit after a second missed period.
Nausea, unless extremely severe, does not compromise an otherwise healthy pregnancy. On the contrary, reflecting the production of a large amount of hormone, this symptom is quite reassuring and is associated with an extremely low rate of miscarriage. The hormone levels result in fragility of small blood vessels in the area of the cervix, often leading to slight spotting, which is harmless and will usually resolve on its own.
By now, pregnancy symptoms are well established. The main physical change is uterine growth. This is often accompanied by stretching of the ligaments that hold the uterus in place. There are often quite noticeable sharp abdominal twinges, especially in a first pregnancy, as this occurs. This is not of concern, however, unless there is also bleeding.
At this point, embryonic organ formation is occurring as the cells begin the process of differentiation. For about the next six weeks, the heart, brain and all other organs start to form. You should make strenuous efforts to avoid potentially harmful influences, such as toxic fumes, alcohol and many drugs. The vast majority of substances to which you may be exposed have not been shown to be harmful, but it is extremely difficult, if not impossible, to study all these items in a scientifically sound fashion. Suffice it to say that even though we live in a society filled with auto exhaust, cigarette smoke and other waste products, the rate of fetal injury remains reassuringly low.
At a physical exam, there will be color changes, softening and uterine growth, which are relatively easy for your physician to appreciate. In addition, ultrasonography can nearly always detect the changes of a healthy fetus.
Your hormones have reached the highest level of the entire pregnancy, will even out and soon begin a gradual decline. The good news is that nausea tends to diminish by the end of this month. Your uterus continues to grow rapidly, and you might notice that you’re beginning to show. Your doctor can usually hear the fetal heartbeat, so 12 weeks is a good time to bring your partner to an office visit to hear it as well. It is remarkable how much that simple experience can bond a future father to his developing child.
You should have established pregnancy care by now, as there are new tests developing that can detect abnormalities such as Down syndrome this early. A twin pregnancy, which requires a highly specialized approach, will now be apparent.
At the 12-week (three-month) point, all organ systems are fully formed. Henceforth, only growth and maturity will occur. The risk of toxic exposure is dramatically reduced, so that drug treatments can be administered now with much less concern about effects upon the developing fetus.
At the beginning of the fourth month, hormone levels stabilize as the unpredictable fluctuations of the first trimester give way to the development of the placenta, which provides continuous nourishment to the fetus. As the fatigue and nausea finally lift, there is a gratifying burst of physical and mental energy. You will develop improved endurance and will be encouraged to seek opportunities to engage in stretching and cardiovascular exercises, which will provide you later on with the ability to cope with the intense physical demands of the third trimester. For this reason, we refer to this segment of pregnancy as the “fitness trimester.”
It is during this month that we begin screening tests to ensure proper fetal development. These may include ultrasound and blood tests so as to determine if more intensive monitoring is required, which is not usually the case. These test results should be available by the end of this month.
By now nearly all women show, although, in the case of a first pregnancy, abdominal muscles may still be quite tight, holding the uterus in and often prompting friends to inquire whether the baby is growing adequately. Fortunately, fetal growth problems rarely occur at this stage, so there’s no need to worry. Ultrasound can generally reveal anatomic details, including your baby’s sex. By 20 to 21 weeks, you can expect “quickening,” or fetal movement.
Stretching of the so called “round ligaments” of the uterus is quite common at this time and can result in sharp sensations in the groin areas, typically associated with sudden changes of position, such as rolling over in bed. They are not at all dangerous and will subside with rest and a warm compress to the area.
As the second trimester comes to an end, your baby’s growth is much more rapid and noticeable. You have a change in posture, as you tend to lean backward for balance. Any fitness exercises you did earlier pay off now, as there can be significant stresses to low back muscles, joints and ligaments. You might feel more uncomfortable during fitness exercises, gradually reducing their intensity and duration.
Screening for diabetes of pregnancy, which is not rare, will be carried out now. If the tests are positive, managing your diet closely can control the condition, which nearly always resolves following pregnancy.
You should start childbirth preparation classes, which will prepare you and your partner for what to expect in labor, dramatically reducing the anxiety associated with the unknown. You will most likely explore such issues as pain relief, relaxation techniques and birth alternatives. It’s important not to formulate rigid birth plans as the events of labor are often dramatically different for each woman, requiring differing labor management methods.
A major focus this month is the monitoring of you and your baby. There seems to be an instinctual increase in self-awareness that makes pregnant women extremely sensitive to subtle changes in the activity pattern of their babies as well as their own symptoms. The fetal surveillance program referred to as “kick counting” begins now, whereby a woman spends some time each evening after dinner counting the number of minutes it takes for her baby to move ten times. For most women, this will take 20 minutes or so. If it were to take more than two hours, she would be instructed to go immediately to the hospital where monitoring would determine if a problem exists. This program continues daily until the birth. Studies have shown it to be of major value in heading off fetal problems before they even occur.
In addition, uterine contractions — which have actually been occurring throughout the pregnancy — become noticeable on a daily basis. Brief and irregular contractions, referred to as Braxton-Hicks, are normal and harmless and quite easily distinguishable from those of actual premature labor, which are long, regular and painful.
Reducing your activity will make you more comfortable while allowing a redirection of blood flow toward the placenta and fetus, which is needed to support the rapid growth of your baby. You should set a firm date for ending employment no later than the end of the eighth month.
Most women become aware that when they are at rest, there is a significant increase both in fetal movements and contractions. This is a positive development, which reflects the fact that resting results in the improved delivery of oxygen and nutrients to both the uterine musculature and the fetus. In addition to these benefits, rest tends to reduce maternal blood pressure and thus diminishes the risk of developing pregnancy-induced hypertension (formerly known as pre-eclampsia).
The final customary laboratory test — a culture to determine whether a pregnant woman is among the 20 percent who carry the Group B streptococcus bacteria — is carried out during this month. If a woman is positive, she will be treated during labor. This innovation of the past 20 years or so has essentially eliminated the past major problem of streptococcal infection of the newborn.
The stage is now set for labor and birth as contractions become stronger and more frequent. You will be seeing your ob/gyn weekly, and there will be close monitoring of your blood pressure. Exams to determine your cervical status might be started. Labor instructions will encourage timing of contractions in order to determine their length, strength and frequency. A good rule of thumb is that when you cannot carry on a conversation during a contraction, true labor is likely. A slightly bloody mucous secretion, called a “bloody show,” tends to signal an impending labor, but there’s no need to worry. If there are concerns about your baby’s well-being, a nonstress test may be run twice a week at the hospital. If it is decided that labor should be induced — brought on artifcially — your physician will explain the pros and cons of doing so.
Regardless of how the process of birth is carried out, the goal is to present a healthy baby to a healthy mother. It is at this momentous and life-changing event that the true benefits of all the preceding months of care become apparent. It is a time to enjoy and celebrate the miracle of life!
David M. Priver, M.D., FACOG, is a San Diego ob/gyn who has been caring for pregnant women for more than 37 years. He has delivered more than 7,000 babies.