From the Publisher

This new Mayo Clinic book on pregnancy provides you with practical information and reassurance on pregnancy and childbirth. Compiled by Mayo Clinic experts in obstetrics, it offers a clear, thorough and reliable reference for this exciting and sometimes unpredictable journey. This comprehensive book includes:

• A month-by-month look at mom and baby


• In-depth "Decision Guides" to help you make informed decisions on topics such as how to select a health care provider, prenatal testing options, pain relief for childbirth, and many others


• An easy-to-use reference guide that covers topics such as morning sickness, heartburn, back pain, headaches and yeast infections, among others


• Information on pregnancy health concerns, including preterm labor, gestational diabetes and preeclampsia, along with an overview on being pregnant when you have pre-existing health conditions such as asthma, diabetes or hyperthyroidism

Product Details

• ISBN: 0060746378
  
• ISBN-13: 9780060746377
• Format: Paperback, 624pp
• Publisher: HarperCollins Publishers
• Pub. Date: April 2004
• Edition Description: First Edition
• Edition Number: 1
• Sales Rank: 5,678

• Read a Sample Chapter

Read a Sample Chapter

Mayo Clinic Guide to a Healthy Pregnancy

HarperResource

Chapter One

Month 1: weeks 1 to 4

My husband and I had been trying to conceive for almost a year. I was delighted when my menstrual cycle was late. My husband, ever cautious, took a wait-and-see attitude.

Your baby's growth during weeks 1 to 4

If you're like most expectant parents, your mind is full of questions. What does my baby look like right now? How big is he or she? How is she or he changing this week? Becoming familiar with how your baby develops, week by week, will help you answer some of those questions. It may also help you understand some of the changes taking place in your body.

Weeks 1 and 2: Preconception and fertilization

Preconception
It may seem a bit strange, but the first week of your pregnancy is actually your last menstrual period before becoming pregnant. Why is that? Doctors and other health care professionals calculate your due date by counting 40 weeks from the start of your last cycle. That means they count your period as part of your pregnancy, even though your baby hasn't been conceived yet.

Conception typically occurs about two weeks after the start of your last menstrual period. When your baby arrives, it will have been about 38 weeks since he or she was conceived, but your pregnancy will have "officially" lasted 40 weeks.

Even while menstruation is happening, your body begins producing a hormone called follicle-stimulating hormone, which fosters development of an egg in your ovary. The egg matures within a small cavity in your ovary called a follicle. A few days later, your body produces a hormone called luteinizing hormone. It causes the follicle to swell and burst through the wall of your ovary, releasing the egg. This is called ovulation. You have two ovaries, but in any given cycle, ovulation occurs from just one of them.

The egg moves slowly into your fallopian tube, which connects your ovary and uterus. There it awaits a fertilizing sperm. Finger-like structures at the junction between your ovary and fallopian tube, called fimbriae, catch the egg when ovulation occurs, keeping it on the right course.

If you have intercourse before or during this time, you can become pregnant. If fertilization doesn't occur, for whatever reason, the egg and the lining of your uterus will be shed through your menstrual period.

Fertilization
This is when it all begins. Your egg and your partner's sperm unite to form a single cell -- the starting point for an extraordinary chain of events. That microscopic cell will divide again and again. In about 38 weeks, it will have grown into a new person made up of more than 2 trillion cells -- your beautiful new baby girl or boy.

The process begins when you and your partner have sexual intercourse. When he ejaculates, your partner releases into your vagina semen containing up to 1 billion sperm cells. Each sperm has a long, whip-like tail that propels it toward your egg.

Hundreds of millions of these sperm swim up through your reproductive system. With the help of your uterus and fallopian tubes, they travel from your vagina, up through the lower opening of your uterus (cervix), through your uterus and into your fallopian tube. Many sperm are lost along the way. Only a fraction of the sperm reach the egg's position in the fallopian tube. Fertilization occurs when a single sperm makes this journey successfully and penetrates the wall of your egg.

Your egg has a covering of nutrient cells called the corona radiata and a gelatinous shell called the zona pellucida. To fertilize your egg, your partner's sperm must penetrate this covering. At this point, your egg is about 1/200 of an inch in diameter, too small to be seen.

Up to 100 sperm may try to penetrate the wall of your egg, and several may begin to enter the outer egg capsule. But in the end, only one succeeds and enters the egg itself. After that, the membrane of the egg changes and all other sperm are locked out.

Occasionally, more than one follicle matures and more than one egg is released. This can result in multiple births if each of the eggs is fertilized by a sperm.

As the sperm penetrates to the center of your egg, the two cells merge to become a one-celled entity called a zygote. The zygote has 46 chromosomes -- 23 from you and 23 from your partner. These chromosomes contain thousands and thousands of genes. This genetic material will determine your baby's sex, eye color, hair color, body size, facial features and -- at least to some extent -- intelligence and personality. Fertilization is now complete.

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Excerpted from Mayo Clinic Guide to a Healthy Pregnancy by Mayo Clinic Excerpted by permission.
All rights reserved. No part of this excerpt may be reproduced or reprinted without permission in writing from the publisher.
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