Some can sense that they are pregnant, but most do not suspect it until they miss the next period. In this article, gain a detailed understanding of fertilization, and learn what goes on in the first 5 weeks of pregnancy. This feature is part of a series of articles on pregnancy. It provides a summary of each stage of pregnancy, what to expect, and insights into how your baby is developing.
First trimester: fertilization, implantation , week 5 , week 6 , week 7 , week 8 , week 9 , week 10 , week 11 , week Second trimester: week 13 , week 14 , week 15 , week 16 , week 17 , week 18 , week 19 , week 20 , week 21 , week 22 , week 23 , week 24 , week 25 , week Ovulation is the process of an ovary releasing an egg.
The medical community measures pregnancy from the first day of the last period, even if fertilization happens several days after the period has ended. For fertilization to occur, sperm must enter the vagina.
This usually, but not always, happens through sexual intercourse. There, the sperm will penetrate and fertilize an egg. Once fertilized, the egg travels down the fallopian tube toward the womb, or uterus, where it will implant in the uterine wall.
Beginning in the ninth week of pregnancy, and until the pregnancy ends, doctors call the developing baby a fetus. The egg comes either from a donor or a woman who wishes to become pregnant. In a laboratory, a specialist doctor works to fertilize the egg with donated sperm. The goal is for at least one fertilized egg to implant and develop. When the egg and sperm unite, they form a zygote.
The zygote contains 46 chromosomes: 23 from the female and 23 from the male. The chromosomes determine the genetic make-up of the fetus, including its sex and inherited physical characteristics, such as:.
They may also help shape factors such as personality, intelligence, and the risk of some health conditions. A zygote inherits one sex chromosome, the X chromosome, from the egg. It also inherits a sex chromosome from the sperm. This may be either an X or Y chromosome. The first option is emergency contraception. Emergency contraception works by preventing or delaying ovulation—the release of an egg from the ovary.
Less commonly, it can work by preventing fertilization of an egg if ovulation has already occurred. It's important to note that emergency contraception is not the same as the "abortion pill" medical abortion with mifepristone and misoprostol. If you take emergency contraception and you're already pregnant, the pill will not harm your pregnancy. For emergency contraception to be effective, it should be used as soon as possible after having unprotected sex. If a person is unable to take it immediately, it might still be effective if taken three to five days after having sexual intercourse.
According to the Food and Drug Administration FDA , emergency contraception is for use after contraceptive failure and is not recommended for routine use. Most forms of emergency contraception are available without a prescription. One example is Plan B One-Step levonorgestrel , as well as its generic versions, which are available at most pharmacies. Next Choice levonorgestrel is available to anyone 17 years and older and is usually available if you ask the pharmacist.
The pill version, ella ulipristal , is only available with a prescription. Whether fertilization occurs within minutes of sex or days later, some people wonder if they will feel pregnant when it happens.
The answer to that question is usually no, but some people claim that they "knew" they had conceived within minutes of sex. It's scientifically impossible to know either way. However, the symptoms of early pregnancy can start as early as a week after having sex or they may take several weeks to start.
That said, some people don't experience any noticeable early pregnancy symptoms, which is also normal. More commonly, it takes between two to four weeks after sex before early pregnancy symptoms are noticeable.
Keep in mind, pregnancy symptoms won't appear until after embryo implantation. It takes time for the fertilized egg to travel from the fallopian tubes and find a landing area in the uterus. When the embryo attaches to the uterine wall, some people experience a bit of light spotting or bleeding. This spotting usually happens close to the time when you would have had your period.
In fact, it's not uncommon for some people to confuse implantation spotting with their period and not realize that they are pregnant.
Not every person will experience spotting or bleeding when implantation occurs. If it does happen to you, don't worry. It's normal and doesn't mean something is wrong with your baby. The test won't be positive until there is enough pregnancy hormone in your body, and this takes time. To get the most accurate results, wait until your period is at least one day late before taking a test. Otherwise, you may get a false negative—even if you are pregnant.
While it's possible that you could conceive within minutes of sexual intercourse, it's more likely to take place hours or even days after you have intercourse. You aren't officially pregnant until the day that an egg is fertilized and implants into the uterus. Get diet and wellness tips to help your kids stay healthy and happy. Royal College of Gynecologists World Congress. Immobilisation versus immediate mobilisation after intrauterine insemination: Randomised controlled trial.
Sperm storage: Distinguishing selective processes and evaluating criteria. Trends Ecol Evol Amst. American College of Obstetricians and Gynecologists. Methods for Estimating the Due Date. Cleveland Clinic. Learn about other infertility risk factors here. Ovulation induction uses hormonal therapy to stimulate egg development and release, or ovulation, the goal being to produce a single, healthy egg.
Learn more. Your overall health is a reflection of your reproductive health. Give yourself a long and healthy life. Consider these tips to stay healthy. Some women have difficulty conceiving because of problems in their reproductive system such as a congenital malformation and require surgery. Learn more here.
Hormones secreted by the hypothalamus, the pituitary and the ovary are the messengers that regulate the menstrual cycle. High-risk pregnancy. Infertility in men. Infertility in women. Donor Sperm Insemination. Intrauterine Insemination IUI. Pre-Implantation Genetic Diagnosis. Patient Education. To become pregnant , the following steps must occur: Sperm transport — The sperm must be deposited and transported to the site of fertilization.
Egg transport — Ovulation must occur and the egg must be "picked up" by the tube. Fertilization and embryo development — Union between the sperm and egg must result. Implantation — The embryo must implant and begin to grow in the uterus. 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. Egg Transport Egg transport begins at ovulation and ends once the egg reaches the uterus.
Fertilization and Embryo Development Following ovulation, the egg is capable of fertilization for only 12 to 24 hours. 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.
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