Stages of Pregnancy

You’re expecting a new baby? Congratulations! This is a very exciting time. Of course, it can also be a little scary.

Both mother and baby go through big changes over the course of 40 weeks. You may have some questions about what to expect.

It’s important to remember that every pregnancy is different – this article is a general informational guide. If you have questions or concerns about your pregnancy, you should contact your doctor immediately. It’s always better to err on the side of safety when it comes to pregnancy. Keeping a close relationship with your doctor throughout your pregnancy can help you and your doctor catch and manage any potential problems as early as possible. It can also help maintain your peace of mind – a less stressful pregnancy is easier on both you and the baby.

With that in mind, let’s take a look at how a pregnancy unfolds and what to expect along the way.

Pregnancy Basics

Over the course of a pregnancy, a single egg cell and a single sperm cell fuse together and grow into a baby. That process typically lasts about 40 weeks, which is between 9 and 10 months. That time is measured in “gestational age.” The gestational age clock starts ticking at the end of the mother’s last menstrual period before the pregnancy. That means that the 40-week countdown probably starts a couple of weeks before conception. It ends at the baby’s birth.

For the sake of convenience, pregnancy is often broken into 3 “trimesters” of 3 months each.

First Trimester

The First Weeks

At this point, you aren’t pregnant yet; you’re involved in a regular menstrual cycle. You’ll have a period. A couple of weeks later, you’ll ovulate. That means your ovaries will release a mature egg into your Fallopian tubes.

Conception

Conception is the moment an egg cell is fertilized by a sperm cell. Conception typically occurs in one of the Fallopian tubes, the structures that connect the mother’s ovaries to the uterus. Once the egg is fertilized, it becomes a “zygote.” The zygote moves down the Fallopian tubes to the uterus over the course of a couple of days. It will float in the uterus and grow for a few days before implanting onto the uterine wall. Not every fertilized egg will turn into a pregnancy; up to half of zygotes pass naturally from the body without ever implanting in the uterine wall.

Some mothers may be unable to conceive through intercourse and seek various types of fertility treatments to increase the likelihood of pregnancy. In some cases, these treatments involve hormones and medications that increase the likelihood that the zygote will implant on the uterine wall. In other cases, an egg and sperm may be combined in a laboratory and the implanted into the uterus. This process is called in vitro fertilization.

Regardless of where conception occurs, pregnancy officially begins when the zygote implants onto the uterine wall.

Embryo

With the exception of in vitro fertilizations, most women will have no signs or symptoms of pregnancy until they miss their first menstrual period. Other early symptoms may arise, including nausea, fatigue, mood swings, and tender or swollen breasts. As pregnancy progresses into the second month, you may start to have more noticeable symptoms including fatigue, nausea, vomiting, and frequent urination.

Whether you can feel your pregnancy or not, the zygote is developing constantly. During the second month of your pregnancy, the zygote will start to develop internal organs and become an embryo. The embryo will have a very simply circulatory system and heart and will start to develop buds that will eventually grow into arms and legs. At this point, the embryo is only a fraction of an inch long.

By the end of the second month, the embryo will grow to be about half an inch long and will start to develop features like eyes, lips, and ears. Depending on the genetic makeup of the embryo, it will start to develop either male or female reproductive structures.

Fetus

After about 10 weeks, the embryo develops into a fetus; at this point the fetus is more than an inch long. Over the next several weeks, the fetus will grow until it measures about 3 inches from the top of its head to the bottom of its buttocks. Its bones will start to harden, its fingernails will start to grow, and its external sex organs will begin to develop.

The pregnancy symptoms you experienced in the first two months will typically get worse during the third month. You may also start to have outbreaks of acne due to hormonal changes. Up until this point, most mothers typically gain only a few pounds.

Second Trimester

Fetal Development Continues

During the fourth, fifth, and sixth months, your baby is continuing to grow. You may be able to see the fetus’s sex with an ultrasound as early as the fourth month, although it often takes longer. During the second trimester, the fetus will grow from just a few inches long to 8 inches or more from head to rump. Its features will continue to develop, as will its internal organs.

Feeling Your Baby

Most mothers start to feel the fetus move around the fifth month. When you start to feel the baby move, it’s called “quickening.” During the second trimester, your breasts may grow by up to 2 cup sizes and may start to produce a small amount of “colostrum.” Colustrum is a very nutrient-rich breast milk that your body will produce until a few days after delivery. It may be yellowish in color due to its high concentration of fats, proteins, and other nutrients.

You may also experience digestive troubles such as heartburn and constipation, although the nausea from the first trimester usually ends by the fourth or fifth month. Because of the added strain on your circulatory system, you may also feel faint or fatigued.

By the end of your second trimester, you may start to experience Braxton-Hicks contractions. These are a sort of practice contraction that helps your body prepare for labor. Braxton-Hicks contractions are perfectly normal and usually feel like a painless squeezing or pressure in your abdomen. If you feel painful contractions or if these contractions are very frequent, you should check with your doctor to make sure that you’re not experiencing preterm labor.

By the end of the second trimester, you’ll gain anywhere from 10-20 pounds. You’ll need to work with your doctor to determine how much weight you should be gaining during pregnancy; it varies by individual based on starting weight, lifestyle, how many children you’ve had, and other factors.

Third Trimester

Getting Ready for Delivery

Over the eighth, ninth, and tenth months of your pregnancy, the fetus will continue to develop and grow. Over these three months, the fetus will grow from about 10 inches from head to rump to more than 20 inches from head to rump. The fetus’s eyes will develop enough to open and its grip will be firm. During the third trimester, the baby will start to be able to respond to stimuli such as music and light. It will be able to kick and stretch with enough force that it can be felt with a hand on the belly.

At the end of the third trimester, as the 40-week mark approaches, the fetus will start to turn into a head-down position in preparation for birth. Right up to delivery, the fetus will continue to gain weight rapidly.

Growing Belly

During the third trimester, your belly will continue to grow. You may experience some back and foot pain and the added strain may cause varicose veins or hemorrhoids to develop. The pressure of your uterus on your bladder means you’ll probably need to use the restroom often and you may experience some leakage. Your uterus may also press on your diaphragm and lungs, leaving you short of breath. You’ll likely gain about 1 pound per week during the third trimester and you may develop stretch marks where your belly and breasts are expanding. Finally, you may have swelling in your hands and feet; your circulatory system is working overtime and can’t clear out excess fluids as efficiently.

During the third trimester, you may have Braxton-Hicks contractions and your breasts may leak small amounts of colostrum. The size of your belly may make it tough to find a comfortable position to sleep in, so you may want to invest in special pillows and other supports to make it easier. During your third trimester, you may experience a “nesting instinct” that makes you eager to set up your nursery and shop for the things your new arrival will need.

As always, be sure to contact your doctor if you’re having frequent or painful contractions. These may be a sign of preterm labor rather than Braxton-Hicks contractions and require medical attention.

The Big Day

After about 40 weeks of growth, change, and anticipation, it’s time to bring your new little one into the world. Over the course of your pregnancy, you’ll work with your doctor and anyone you want to be involved to decide how you want to deliver your baby. You may want to use an epidural to help manage pain or you may want to avoid painkillers. You may want to deliver in a hospital, in a birthing center, or at home. You’ll want to have a plan in place so that you know what to expect, but remember that you can always change your mind. When you’re in labor, you’re the boss.

Delivery is different for everyone – it may take only a few hours or it may take a few days. It is typically divided into 3 main stages. As with any pregnancy-related issue, contact your doctor if you have any questions or concerns about starting labor.

Stage 1

Labor starts when you start to have strong, regular contractions. The contractions will gradually get closer together and last longer, until they last for 30 seconds to a minute and come every 5 minutes. During this time, your cervix will start to thin out and dilate to make way for the baby.

At some point during labor, your water will break. That means the amniotic sac which surrounds the baby will rupture, letting amniotic fluid spill out. Some mothers will have only a small amount of amniotic fluid leak out while others will have larger quantities. When your water breaks, it’s time to get down to the serious business of labor. Without amniotic fluid, you and your baby are at risk for infection. If your water breaks before labor starts, your doctor or midwife may want to induce contractions to get the process moving.

Stage 2

When your cervix is fully dilated to 10 centimeters, you enter stage 2 of labor. Stage 2 ends when your baby is born. During this time, you will have strong and frequent contractions. The baby will move down toward the birth canal, putting pressure on your bowels – many women have bowel movements during delivery due to this pressure.

During stage 2, it’s time to push. Your uterus will contract on its own. When you bear down at the same time, you push the baby down through the birth canal. Over time, the baby will pass all the way through until its head is at the vaginal opening. This is your first chance to touch your baby’s head. You may also request a mirror to see it for the first time. When the widest part of the baby’s head passes through the vaginal opening, it’s called “crowning.” After the baby crowns, the doctor or midwife will check to ensure that the umbilical cord isn’t wrapped around the baby’s neck. Then the baby can pass the rest of the way through the birth canal.

Your baby is born! The doctor or midwife will clamp the umbilical cord, towel off your new little one, and may suction excess mucus out of the mouth. Either your doctor or a loved one will cut the cord. After 40 long weeks of waiting, you’ll get to hold your baby for the first time.

Stage 3

The baby is born, but labor isn’t quite over yet. During stage 3, you’ll continue to have contractions. The placenta will detach from the uterine wall and you’ll be able to deliver it with a couple of quick pushes.

Once you’ve delivered the placenta, your uterus will contract – you’ll be able to feel it pull up in your belly. That helps it clamp down on all the blood vessels where the placenta was attached so that you don’t bleed. If your uterus doesn’t contract right away, your doctor or midwife may massage it to encourage it to tighten up.

Finally, you may need a few stitches to repair your perineum. The perineum is the skin that stretches between the vagina and the rectum and is prone to tear during delivery. If you experience tearing, your nurse, midwife, or doctor will close up the tear with a few stitches.

C-Sections and Complicated Deliveries

A cesarean section, or “c-section,” is a procedure by which the baby is removed through an incision in your abdomen, rather than delivered vaginally. You may have a c-section for a number of reasons. If you’re in distress, if the baby’s in distress, if the baby is trapped in the birth canal and may not be getting enough oxygen, or if other complications arise, a c-section allows your doctor to remove the baby quickly and address any issues.

If you have a high-risk pregnancy or have had a c-section before, you may schedule your c-section in advance. In some cases, complications during labor may require an emergency c-section. A planned c-section often leaves a scar under your bikini line, so that it doesn’t show when you wear a swimsuit. An emergency c-section may leave a scar higher on your belly.

In general, midwives and birthing centers are not equipped or qualified to deal with complicated deliveries. If you have a high-risk pregnancy, you may need to plan to deliver in a hospital. If you’re at home or at a birthing center and complications arise, you may need to be transferred to a hospital so that you and your baby can get the treatments you need.

Afterward

Whether through vaginal birth or through a c-section, your new little one has finally arrived. Your doctor or midwife will perform an Apgar test right after your baby is born and then again a few minutes later to check for proper breathing, muscle tone, and reflexes.

If there are any complications, your doctor may put the baby in an incubator in the room to keep the baby warm during tests and treatments. In serious cases, your baby may require treatment in the newborn intensive care unit. Your doctors and nurses will keep you informed of any treatment your baby requires. Most babies, of course, are perfectly healthy and don’t require any special care.

After the Apgar test, you can ask to hold and cuddle with your baby. Skin-to-skin contact is important for bonding. If you’re planning to breastfeed your baby, you can start immediately. Your breasts will produce colostrum for the first few days to give the baby an extra kick of nutrients, after which you’ll start to produce regular breast milk.

Once you’ve had a little while to bond with your baby, a doctor or nurse will make a copy of your baby’s footprints. Your baby will also get some antibiotic eyedrops to prevent common eye infections and a shot of vitamin K to help the baby’s blood clot normally.

After a few hours, your baby will get a complete pediatric exam, including baby’s first vaccine (for hepatitis B) and a first bath to wash off the remnants of the delivery process. Within 48 hours, your baby will have a simple blood test done to check for a variety of genetic and metabolic disorders and may also have a hearing test.

You’re A New Parent!

If you or the baby experienced complications, one or both of you may need to spend some time in the hospital to recover. If you had an uncomplicated vaginal birth, you can usually take your new baby home after a couple of days.

Congratulations on your new arrival!