What is conceive in pregnancy

To become pregnant, the following steps must occur:

These steps are described below.

Sperm Transport

The transport of sperm depends on several factors:

• The sperm must be capable of propelling themselves through the environment of the female vagina and cervix.
• This environment, which is under cyclic hormonal control, must be favorable to admit the sperm without destroying them.
• The sperm must possess the capability of converting to a form that can penetrate the cell membrane of the egg (capacitation).

Following ejaculation, the semen forms a gel that protects it from the acidic environment of the vagina. The gel is liquefied within 20 to 30 minutes by enzymes from the prostate gland. This liquefaction is important for freeing the sperm so transportation may occur. The seminal plasma is left in the vagina.

The protected sperm with the greatest motility travel through the layers of cervical mucus that guard the entrance to the uterus. During ovulation, this barrier becomes thinner and changes its acidity, creating a friendlier environment for the sperm. The cervical mucus acts as a reservoir for extended sperm survival.

Once the sperm have entered the uterus, contractions propel the sperm upward into the fallopian tubes. The first sperm enter the tubes minutes after ejaculation. The first sperm, however, are likely not the fertilizing sperm. Motile sperm can survive in the female reproductive tract for up to five days.

Egg Transport

Egg transport begins at ovulation and ends once the egg reaches the uterus. Following ovulation, the fimbriated, or finger-like, end of the fallopian tube sweeps over the ovary. Adhesive sites on the cilia, which are located on the surface of the fimbriae, are responsible for egg pickup and movement into the tube. The cilia within the tube, and muscular contractions resulting from the movement of the egg, create a forward motion. Transport through the tube takes about 30 hours.

Conditions such as pelvic infections and endometriosis can permanently impair the function of the fallopian tubes, due to scarring or damage to the fimbriae.

Fertilization and Embryo Development

Following ovulation, the egg is capable of fertilization for only 12 to 24 hours. Contact between the egg and sperm is random.

Once the egg arrives at a specific portion of the tube, called the ampullar-isthmic junction, it rests for another 30 hours. Fertilization — sperm union with the egg — occurs in this portion of the tube. The fertilized egg then begins a rapid descent to the uterus. The period of rest in the tube appears to be necessary for full development of the fertilized egg and for the uterus to prepare to receive the egg.

Defects in the fallopian tube may impair transport and increase the risk of a tubal pregnancy, also called ectopic pregnancy.

A membrane surrounding the egg, called the zona pellucida, has two major functions in fertilization. First, the zona pellucida contains sperm receptors that are specific for human sperm. Second, once penetrated by the sperm, the membrane becomes impermeable to penetration by other sperm.

Following penetration, a series of events set the stage for the first cell division. The single-cell embryo is called a zygote. Over the course of the next seven days, the human embryo undergoes multiple cell divisions in a process called mitosis. At the end of this transition period, the embryo becomes a mass of very organized cells, called a blastocyst. It's now believed that as women get older, this process of early embryo development is increasingly impaired due to diminishing egg quality.

Implantation

Once the embryo reaches the blastocyst stage, approximately five to six days after fertilization, it hatches out of its zona pellucida and begins the process of implantation in the uterus.

In nature, 50 percent of all fertilized eggs are lost before a woman's missed menses. In the in vitro fertilization (IVF) process as well, an embryo may begin to develop but not make it to the blastocyst stage — the first stage at which those cells destined to become the fetus separate from those that will become the placenta. The blastocyst may implant but not grow, or the blastocyst may grow but stop developing before the two week time at which a pregnancy can be detected. The receptivity of the uterus and the health of the embryo are important for the implantation process.

In order for pregnancy to happen, sperm needs to meet up with an egg. Pregnancy officially starts when a fertilized egg implants in the lining of the uterus. It takes up to 2-3 weeks after sex for pregnancy to happen.

How do people get pregnant?

Pregnancy is actually a pretty complicated process that has several steps. It all starts with sperm cells and an egg.

Sperm are microscopic cells that are made in testicles. Sperm mixes with other fluids to make semen (cum), which comes out of the penis during ejaculation. Millions and millions of sperm come out every time you ejaculate — but it only takes 1 sperm cell to meet with an egg for pregnancy to happen.

Eggs live in ovaries, and the hormones that control your menstrual cycle cause a few eggs to mature every month. When your egg is mature, it means it’s ready to be fertilized by a sperm cell. These hormones also make the lining of your uterus thick and spongy, which gets your body ready for pregnancy.

When a sperm cell joins with an egg, it’s called fertilization. Fertilization doesn’t happen right away. Since sperm can hang out in your uterus and fallopian tube for up to 6 days after sex, there’s up to 6 days between sex and fertilization.

If a sperm cell does join up with your egg, the fertilized egg moves down the fallopian tube toward the uterus. It begins to divide into more and more cells, forming a ball as it grows. The ball of cells (called a blastocyst) gets to the uterus about 3–4 days after fertilization.

Implantation usually starts about 6 days after fertilization, and takes about 3-4 days to complete. The embryo develops from cells on the inside of the ball. The placenta develops from the cells on the outside of the ball.

When a fertilized egg implants in the uterus, it releases pregnancy hormones that prevent the lining of your uterus from shedding — that’s why people don’t get periods when they’re pregnant. If your egg doesn’t meet up with sperm, or a fertilized egg doesn’t implant in your uterus, the thick lining of your uterus isn’t needed and it leaves your body during your period. Up to half of all fertilized eggs naturally don’t implant in the uterus — they pass out of your body during your period.

What are early pregnancy symptoms?

Many people notice symptoms early in their pregnancy, but others may not have any symptoms at all.

Common signs and symptoms of pregnancy can include:

• Missed period

• Swollen or tender breasts

• Nausea and/or vomiting

• Feeling tired

• Bloating

• Constipation

• Peeing more often than usual

Some early pregnancy symptoms can sometimes feel like other common conditions (like PMS). So the only way to know for sure if you’re pregnant is to take a pregnancy test. You can either take a home pregnancy test (the kind you buy at the drug or grocery store), or get a pregnancy test at your doctor’s office or local Planned Parenthood Health Center.

How do people get pregnant with twins?

There are 2 ways that twins can happen. Identical twins are made when 1 already-fertilized egg splits into 2 separate embryos. Because identical twins come from the same sperm and egg, they have the same genetic material (DNA) and look exactly alike.

Non-identical twins (also called “fraternal” twins), are made when two separate eggs are fertilized by two separate sperm, and both fertilized eggs implant in the uterus. This can happen if your ovaries release more than one egg, or during certain kinds of fertility treatments. Non-identical twins have completely different genetic material (DNA), and usually don’t look alike. They’re the most common type of twin.

What is gestational age?

The term “gestational age” basically means how far along into a pregnancy you are. Gestational age is counted by starting with the first day of your last menstrual period (called LMP).

Gestational age can be kind of confusing, since it measures pregnancy from your last period — about 3-4 weeks BEFORE you’re actually pregnant. Common knowledge about pregnancy says it lasts 9 months, and it’s true that you’re usually pregnant for about 9 months. But the way pregnancy is measured makes it a little longer. A typical full-term pregnancy ranges from 38-42 weeks LMP — around 10 months.

Many people can’t remember the exact date of their last menstrual period — that’s totally okay. Your nurse or doctor can find out the gestational age using an ultrasound.

More questions from patients: