The Expectant Mother's Guide
CHAPTER 1
Pregnancy and Breast-feeding: What Every Mother Needs To Know
Diagnosis
The first sign of pregnancy is usually a missed menstrual period. However, some women may have other symptoms of pregnancy before they miss their first period. These may include morning sickness, tender breasts, enlarged breasts, more frequent urination, and darkening of the nipples. Pregnancy is most often confirmed by detecting the presence of human chorionic gonadotropin (HCG) in the blood or urine. Some laboratories are sophisticated enough to detect levels of HCG in the blood 7 to 9 days after the egg is fertilized by the sperm. However, most blood tests confirm pregnancy 6 to 10 days after the egg has implanted itself into the uterus, which is usually within the first week after a missed period. These tests use radioimmunoassay (RIA) or enzyme-linked immunosorbent assay (ELISA) techniques to confirm pregnancy. They are more accurate and reliable than a urine pregnancy test.
Home pregnancy tests use monoclonal antibodies to detect the presence of HCG in the urine. These tests can detect the presence of HCG in the urine one to two weeks after the first day of a missed period. Home pregnancy tests have become much more reliable in recent years. When used correctly, they are 97 percent accurate. Afalse negative result, in which the patient is pregnant but the test indicates she is not, can occur up to 25 percent of the time. Usually these false negative results are due to errors in following the directions of the test. If a woman receives a negative result from a home pregnancy test and still believes she is pregnant, she should retest in about a week, or see her doctor. False positive results, in which the patient is not pregnant but the test indicates she is, occur less than 4 percent of the time. Women taking birth control pills (oral contraceptives) will not receive false positive results. If a woman receives a positive result from a home pregnancy test, she should assume she is pregnant and make an appointment to see her doctor.
The one problem with home pregnancy tests is their inability to consistently detect an ectopic pregnancy, implantation of the egg in an area outside the uterus like the fallopian tubes. Home pregnancy tests fail to detect 50 percent of all ectopic pregnancies. Women who experience negative results and the continued absence of menses should make an appointment with their doctor to rule out an ectopic pregnancy.
Tips for Using Home Pregnancy Kits
1. Kits with sticks on which the woman urinates are easier to use than those by which the urine must be collected in a cup.
2. Follow the directions carefully.
3. Wait until at least the second or third day after menses was supposed to begin before you test.
4. Use a morning urine sample for the test. The levels ofHCG, if present, will be concentrated at this time.
5. Test the urine sample immediately after collection. If you cannot test the sample at this time, place the samplein the refrigerator. Once the sample has been placed in the refrigerator, you must allow the sample to warm to room temperature before testing.
6. Any sediment or solids in the sample should not be mixed or shaken up. Let them settle on the bottom of the collection cup.
Calculating a Due Date
Now that you know you are pregnant, the next question is usually, when am I due? The normal length of pregnancy is 267 days from the time a woman's egg is fertilized by the sperm, or 280 days from the first day of the last menstrual period (about 40 weeks). There are various charts and tables that allow doctors to estimate the due date of the baby but it is usually confirmed by ultrasound. Women can use a mathematical formula to estimate their own due date called Nagele's rule. To calculate the due date using Nagele's rule, take the date of the first day of the last menstrual period, subtract three months, and add 7 days. For example: If the first day of the last menstrual period was July 10, you subtract 3 months from July 10 and add 7 days (July 10 - 3 months = April 10 + 7 days = April 17 as the expected due date). This method is usually accurate to within 2 weeks of delivery and works best in women with a normal 28-day cycle.
Development of the Baby
Many expectant parents do not realize that a baby actually begins growing and developing even before the egg implants itself into the uterus, but let's start the story with the point at which fertilization occurs. Fertilization of the mother's egg by the sperm occurs in thefallopian tubes. Within 24 hours of fertilization, the egg, now called an embryo, begins to grow and multiply. This initial growth and development occurs for about 6 days as the embryo continues its journey down the fallopian tubes to the uterus. During these first 6 days, the embryo receives its nutrition from secretions released from the mother's cells that line the fallopian tubes.
At about day 6, the embryo arrives at the uterus and floats freely, receiving its nutrients from the secretions produced by the lining of the uterus. On or about day 7, the embryo attaches itself to the lining of the uterus and then begins implanting itself into the endometrium. The embryo secretes enzymes that erode a small portion of the uterine lining. By day 10, the embryo has implanted itself firmly and completely into the endometrium.
After implantation, the amnion begins to develop and will eventually surround the entire embryo. This is also referred to as the amniotic sac. The space between this sac and the embryo is filled with clear fluid called amniotic fluid. This keeps the embryo moist and provides a cushion against mechanical injury. The placenta is also beginning to develop about the same time as the amnion. The placenta is the organ of exchange or pathway between the mother and baby. It is the organ by which nutrients are passed to the baby from the mother, as well as the channel by which waste is removed from the baby to be excreted by the mother. The placenta also secretes hormones such as estrogen, progesterone, and HCG.
Estrogen stimulates the uterus to enlarge, the breasts to grow and develop to prepare for breast-feeding, and increases the elasticity of the pelvis in preparation for birth. Progesterone provides early nutrition for the embryo and prevents the uterus from contracting, which prevents spontaneous abortions, and may also help prepare the breasts for breast-feeding. Probably the most important hormone secreted by the placenta is HCG. HCG signals the body that pregnancy has begun and causes additional release of estrogen and progesterone by the body. This action further stimulates the endometrium and placenta to continue developing. If HCG was notpresent, the endometrium would begin to deteriorate, disintegrate, and be sloughed off along with the embryo, and menses would begin. Therefore, HCG is essential for a pregnancy to be maintained by the body.
The stages of pregnancy are divided into three equal periods or trimesters, each containing three months. The first trimester is months 1 through 3, the second, months 4 through 6, and the third, months 7 through 9. From the time the egg is fertilized through the end of the eighth week of pregnancy, the developing organism is referred to as an embryo; from the ninth week to delivery the baby is referred to as a fetus. At nine weeks, the embryo actually contains most of its important body parts and that's why it is referred to as a fetus.
The most crucial time in the development of the baby is probably the first trimester. In the first two to three weeks of development, the spinal cord and neural plate (which eventually become the central nervous system) are formed. During the first three weeks of pregnancy, tissue that will later become the heart is already beginning to grow and take shape. In fact at the end of the first month of pregnancy, an S-shaped heart is beating on its own about 60 times per minute. Also by the end of the first month the three primary areas of the brain have already formed; small buds that will become the limbs are beginning to develop; the beginning of what will be the eyes and ears are visible; and the liver and blood vessels are forming.
During the second month of pregnancy, all major organs continue to grow and develop and the embryo becomes capable of movement. The major veins and arteries assume their final position in the embryo and the heart is now normally shaped and developed, albeit in miniature form. The brain is also beginning to send signals to the major organs to help regulate their function and a few minor reflexes are now evident. Also during the second month, the sex organs, bones, and muscles of the child have begun to form internally. By the end of the second month, all of the major organs arepresent, including the limbs and head, and the embryo looks like a little minature human being.
During the third month, the fetus begins breathing movements, which transfer amniotic fluid in and out of the lungs. Also, the eyes and ears are beginning to assume their final positions on the head and the arms and legs are very distinct. The fetus can carry on some sucking movements and the sex of the child is clearly identifiable. By the end of the third month, the fetus weights about 14 grams (½ ounce) and is about 56 millimeters (over 2 inches long).
During months 4 through 6, the fetus continues to grow and develop. The fetus is able to move independently throughout the amniotic sac and the heart is beating about 150 times a minute. At about the fifth month of pregnancy, the heartbeat can be heard using a stethoscope and the fetus is 250 millimeters (10 inches) in length, which is approximately half of its total length at birth.
The greatest amount of growth in the fetus occurs during the last trimester of pregnancy. The weight of the fetus will almost double during months 8 and 9. Also during this time, the final development of almost all the tissues and organs is taking place. The development of the ability of the fetus to regulate its own temperature and breathe air occurs during this part of the pregnancy.
Medication Use and Pregnancy
Most medical sources estimate the chances of a baby being born with a major birth defect at about 3 percent. Another 3 percent have birth defects that usually appear in the first year after birth. The cause of 40 percent of these birth defects is unknown. Another 12 to 25 percent of birth defects are caused by genetic defects in the infant or mother, of which Down syndrome is the most common. About 20 percent are due to interactions between hereditary factors and the environment. The causes of these are largely unknown. Finally, about 5 to 10 percent of all birth defects are the result ofchemicals, drugs, and/or infections or diseases the mother has while pregnant. This may seem like a small percentage, but many of these are avoidable with proper education and counseling on drug therapy choices from the patient's doctor and pharmacist. It is important to know that almost every medication that a mother takes will reach the fetus. In fact, sometimes the fetus is receiving the same amount of drug as the mother via the umbilical cord. Therefore, pregnant women should think very carefully about the potential effects on the fetus before taking any medication.
There are two important factors that determine the potential harm to the fetus of a medication, length of exposure and age of the fetus at exposure. From fertilization to two weeks after fertilization, the embryo is relatively resistant to the effects of drugs. At this point in development, it is usually an "all or none response." The embryo will either survive from exposure to the drug or be unaffected. Major birth defects usually do not occur from drug exposure during this time.
Little is known regarding at which stage or trimester of pregnancy the fetus is at greatest risk for developing birth defects from medication use. However, weeks 2 through 10 appear to be a very critical time period. During this time, most of the major organs are forming and it may be when many birth defects occur. This is not to say, however, that medications taken during the second and third trimesters will not cause birth defects. Birth defects due to exposure to certain drugs can and do occur during the second and third trimesters, including central nervous system (CNS) development defects, growth problems, mental development disorders, reproductive defects, and many others. Finally, the longer a woman takes a drug the greater the risk of birth defects due to repeated exposure.
A definitive cause-and-effect relationship between a specific drug and birth defects can be hard to prove, because of many other factors and exposures a woman may experience during pregnancy. It's unethical to test the effects of medications on the fetus, so muchof our information regarding the potential of drugs to cause birth defects comes from cases reported by physicians and from animal testing. Many medications are tested on pregnant rats, mice, and rabbits. These results may provide some useful insight into the potential effects in humans, but the true effect on the human fetus is still not known.
The Food and Drug Administration (FDA) instituted a ratings system for drugs marketed after 1980 based upon their perceived safety for use during pregnancy. The safest drugs are classified as Category A. These drugs have been shown to be of virtually no risk to the fetus and safe to take. Very, very few drugs are classified in Category A. Category X drugs, on the other hand, have been shown to definitely cause birth defects in the fetus when taken during pregnancy. The other categories--B, C, and D--fall somewhere in between categories A and X. A full explanation of each of the FDA categories of drug risk follows in Table 1.
Medication Use and Breast-feeding
Human milk is very complex and its exact chemical makeup is not known, but it does contain just the right amount of lactose, water, fatty acids, amino acids, and other components essential for the proper development of a young infant. Formula is similar to breast milk, but it is not a perfect match. Human milk contains at least 100 ingredients not found in formula. These ingredients include living cells, hormones, and active enzymes. Human milk also contains antibodies to disease and macrophages, cells that kill bacteria,fungi, and viruses. Therefore, when the mother is exposed to disease she makes antibodies to fight this disease. These antibodies are transferred to infants to help them fight off the disease as well. An infant's immune system will receive a great deal of help fighting infection and viruses. There is little doubt that breast milk is better for infants than formula.
Another benefit of breast milk is that it is always sterile when taken straight from the breast. Therefore, most common illnesses, such as colds, flu, skin infections, and diarrhea, cannot be passed from the mother to the infant through breast milk. The HIV virus, however, can be passed from mother to infant through breast milk. Much of what the mother eats and ingests is also found in breast milk. This includes many medications.
As a general rule, medications that are given to a mother reach the infant in much smaller quantities through her breast milk. However in some cases, even these smaller amounts can be harmful to the infant. When a breast-feeding mother takes a medication, her first response may be to stop breast-feeding altogether. This is not always best for the infant. A better goal is to minimize infant exposure to drugs in the breast milk, with minimal disruption in regular nursing patterns. The best alternative is to choose drugs that do not get into the breast milk or are known not to have adverse effects on the infant. But this is not always possible. Here are some tips, in order of importance, to follow when taking medication while breast-feeding.
1. Always talk to your doctor or pharmacist first.
2. Don't take the medication if it is not essential. For example: If you can suffer through the symptoms of a cold without taking medication, do it.
3. Choose drugs that do not get into the breast milk or are found in very low concentrations in breast milk. Your doctor or pharmacist can recommend these to you.
4. Wherever possible, use topically applied creams, ointment, nasal sprays, etc. The medications in these products are less likely to get into the breast milk.
5. Express or pump some milk from the breast and then take the medication. At the next feeding or two, use the milk that you have expressed or pumped.
6. Avoid nursing at times of peak drug concentration in milk. As a rule of thumb, peak concentration of a drug occurs in the milk about 1 to 3 hours after an oral dose. Therefore, nurse the infant just before you take a dose of medicine. This method works best for infants who nurse at regular 3- or 4-hour intervals rather than those still nursing every 2 hours or so.
7. Take the medication before the infant's longest sleep period. If the infant sleeps all night, take the medication after you put the infant down for the night.
8. Stop breast-feeding temporarily if you are taking the medication for a short time period and use formula instead. To maintain milk flow, it will be necessary to express or pump breast milk during this time. Just discard the expressed milk.
Each chapter in this book provides information regarding the risk to the infant of a particular drug, chemical, or toxin when breast-feeding. For many drugs, we do not currently know if they pass into breast milk or if they are a danger to the infant. Therefore, some entries state that researchers are unsure of the potential effects. In some instances, a drug may be safer to use during pregnancy than during breast-feeding. This could be because the drug is found in higher concentration in breast milk and potentially could do more harm to the infant.
The information within this book should only be used as a generalguide to a broad spectrum of substances that can be harmful to the developing infant. Always consult your doctor or pharmacist regarding the safety of any medication, herb, vitamin supplement, or chemical and its potential effect on a breast-feeding infant.
OVERALL RECOMMENDATION: Before taking any prescription medication, over-the-counter drug, herbal or homeopathic product, vitamin, or the like, always consult your doctor or pharmacist first. If you can do without it, avoid it. Do not rely solely on the information from books, the Internet, friends, or family regarding the safe use of medication during pregnancy. Only a qualifled doctor or pharmacist can provide this information.
THE EXPECTANT MOTHER'S GUIDE TO PRESCRIPTION AND NONPRESCRIPTION DRUGS, VITAMINS, HOME REMEDIES, AND HERBAL PRODUCTS. Copyright © 2001 by Donald L. Sullivan, R.Ph., Ph.D. All rights reserved. No part of this book may be used or reproduced in any manner whatsoever without written permission except in the case of brief quotations embodied in critical articles or reviews. For information, address St. Martin's Press, 175 Fifth Avenue, New York, N.Y. 10010.
