The Complex Science of Conceiving Children

Chances are, you were told at school that you can get pregnant any time you have sex, so don’t have sex. But for the most part it’s a lie to get you to keep it in your pants – it’s actually not that easy to conceive.

Even if you and your heterosexual partner have been doing it like rabbits for a year, you still only have an 85% chance of becoming proud parents of an embryo by the end of that time. Many people already know this and find it difficult to get pregnant or stay pregnant – about 10% of women, depending on how you want to define it. (There are no reliable numbers for the corresponding indicator in men .) But even when all internal organs are in working order, the likelihood of pregnancy is lower than you think, hence the phrase ” trying to get pregnant.”

Here’s an unfortunate fact: 19% of young women and 13% of young men in one survey published in The Sexual and Reproductive Health Perspectives believed they were infertile , and many of them stated that the reason for this belief was that they had sex. without contraception and pregnancy did not occur. “Our understanding of the likelihood of conception is really flawed,” says Chelsea Police, lead author of the study.

Most of the people she surveyed believed that the chance of getting pregnant on any given day was 50% or more. In truth, this is about a 3% chance on average, ranging from 0% during your period to about 10% just before ovulation. Time matters.

Menstrual cycle is greater than period on / period off

You know that women have a monthly reproductive cycle and that removing the blood-like lining of the uterus is part of that cycle. So far, so good. But if this is where your knowledge ends (and, unfortunately, for many non-women, this is where it ends), we need to talk.

The period between periods is not just a three-week lull, but the hormonal dance of biology. Ignoring this is like looking at a ballet theater from the outside, saying, “Hmm, a lot of people leave this building at 11:00 pm on Saturday night.” It only happens because there is something really interesting going on inside.

The first day of a woman’s period is considered day 1 of her cycle simply because it is the only event in the month that you will definitely notice. This is where we sync our clocks.

For the first half of the cycle, we are in the follicular phase , so called because in the ovary, the egg matures inside its covering, also known as the follicle . In fact, several follicles start to grow , but only the fastest growing of them ovulates.

This follicle releases its egg on about day 14 of a 28-day cycle. If your cycle is longer than usual, the follicular phase is probably the longest part .

Ovulation occurs when the follicle ruptures and a small egg moves freely through the fallopian tubes into the uterus . Sometimes you havecramping or spotting , but it’s also completely normal not to know when you are ovulating.

The next 14 days or so is the luteal phase . While the egg is not working, its old follicle has developed into acorpus luteum (Latin “yellow body”), which continues to secrete hormones – now, in particular, hormones that make the uterus prepare for pregnancy. PMS symptoms can sometimes even appear similar to those of an early pregnancy .

We didn’t notice the hormonal surges that accompany this whole crazy dance. There is a more detailed overview here if you want to know a little more, and if you want to know a lot more, the best way to do it is to keep track of what’s going on in your own body. Start with an app like Eve (formerly Ruby) or Clue , or just start marking your period and symptoms in a simple calendar.

Once you do this, you will notice that most of the annoying symptoms occur in the second half of the cycle, hence the name ” premenstrual syndrome ” or PMS. Note, there are stupid people everywhere: if you joke that someone should be capricious because she is “on a rag”, you are not only rude, but also demonstrate your ignorance. As soon as the woman started her period, PMS ended and she returned to the follicular phase.

You can’t just get pregnant any time of the month.

You may recall the half-truths from your sex education sessions ( if you ever had any ) that a woman can get pregnant at any point in her cycle, so you should be extra vigilant about contraceptive use every time. In fact, you or your partner have virtually no chance of getting pregnant during your period.

It makes sense why teachers don’t emphasize this fact: keeping track of the time in the month is not the best birth control strategy for most people. This is a particularly bad idea for teens, who cannot count on their menstrual periods to always be the same length . On the other hand, understanding where you are in your cycle can help women understand their bodies. If you are only looking at the calendar, this is not a very effective ” rhythmic method ” that you were probably warned against. If you use other clues and symptoms to find out when you are fertile, this is known as ” fertility awareness ” or “natural family planning.”

Other forms of contraception, such as the good old condoms , are much more reliable at preventing pregnancy than fertility awareness methods. We are not telling you to give up other methods of birth control, but simply helping you understand what is happening during the month. On the other hand, knowing when you are ovulating is very helpful in getting pregnant if you are trying to.

Let’s bring the day of ovulation a little closer. You might think this is a good day for pregnancy, but the party is almost over there. In order for the egg and sperm to meet at the right time, you need to have sex a few days before ovulation.

This is because the reproductive tract can hold sperm for several days , directing it to a storage area near the ovary. As the time of ovulation approaches, something in the female reproductive system overactivates the sperm , so when an egg pops out of the follicle, it can be fertilized immediately.

Therefore, if you are trying to conceive, the most likely time will be the week before ovulation , especially the last two or three days in this window.

This study, published in Human Reproduction, shows the daily likelihood of how likely a woman is to get pregnant every day. During the week of menstruation, almost no one gives birth. The line is close to zero (non-zero probabilities may reflect accounting errors rather than be fertile at the time), and then the likelihood of sex leading to pregnancy rises around where we assumed there might be a fertile window. be, for most people. Some people still get pregnant after day 14, but remember that these numbers come from large groups of people, so later conceptions are more likely to be in people with a longer cycle and therefore a fertility period that comes at the end. months.

Fertility awareness can work like birth control, but there are some serious caveats. First, your cycles should be about the same length each time, and if not, you need to be aware of this uncertainty. Second, you need to be with a partner you know and trust as you count on them to get rid of your STIs. And third, fertility awareness methods have a lot of failures . They are no worse than condoms if you really know what you are doing, but very few people seek to know the inner workings of their womb (or their partner’s womb) every single day .

Tracking means more than just looking at your calendar. Signs of ovulation include:

  • On the day of ovulation, the body temperature rises sharply by half a degree.
  • The cervix, which you can feel by sticking your finger into your vagina (not for the weirdly touching crowd), feels softer when you’re fertile (just before ovulation) than during other periods of pregnancy. month.
  • Cervical mucus, which you might otherwise call vaginal discharge, changes its consistency. When you are fertile, it is thick and sticky.
  • Ovulation test kits will test positive a day or two before ovulation.

Keeping track of these things can be tricky. For example, body temperature needs to be measured at the same time and under the same conditions every day to detect this tiny spike, so the typical method is to take your temperature first thing in the morning before you get out of bed. … If you want to sleep, you set an alarm, take your temperature, record it, and then go back to sleep. If this sounds like a fun hobby, you need a powerful app like Ovia or Fertility Friend to analyze all the data correctly.

Remember that even with a lot of data, it is difficult to use this understanding to avoid pregnancy. The first few days of your period are probably okay, but you can’t always predict exactly when your fertile period will come. When you are trying to conceive, fertility awareness is much more beneficial.

How long does it actually take before you officially get pregnant

Once a pregnancy has begun, calculating the age of a small peanut is harder than you might think.

Let’s talk about the end of pregnancy first, as it’s easier. Pregnancy according to the textbook is considered to be 40 weeks long, while a baby is “full-term” (neither early nor late) if he is born between 37 and 42 weeks. In other words, the deadline is an estimate, not a deadline. ( I look at you, everyone who offered snide comments and looked at you disapprovingly when you asked the date when I was supposed to be born, and I said “yesterday.”

But on the other hand, this is even stranger. Here’s your mind blowing fact: there is no one week of pregnancy.

This is because a pregnancy is not counted from the moment it actually started, but from the start of the last regular menstruation of the pregnant woman. This is what the timeline actually looks like for a person with a 28-day cycle:

  • Day 1 of your “pregnancy”: Your period has begun. You are NOT pregnant.
  • Days 8-14 : Somewhere in this window, you have a fateful night in your bag that you, in hindsight, either cherish or regret.
  • Day 14 : Ovulation. The egg finally meets the sperm. The fertilized egg divides, divides again, and so on.
  • Day 20-22 : A fertilized egg in the blastocyst stage is implanted into the lining of the uterus.
  • Day 28 : The implanted embryo now secretes enough hCG hormone to be detectable in urine. Finally, you can pee on a stick and see two lines. Congratulations and / or condolences! Your morning sickness is approaching and will arrive in about two more weeks .

So, you were “two weeks pregnant” when the egg met sperm, “three weeks” when the zygote actually attached to your body, and “four weeks pregnant,” the earliest you could know about. (Note that this is the same date that your periods usually show up: by the end of your cycle, you either get your period or a positive pregnancy test.)

By the way, because of this time it is good for a woman to always know when she had her last period. Thus, if you accidentally get knocked down, you do not have to wait for an ultrasound so that the doctor can guess how old the child is; you can just tell them. You can also avoid the “what if you’re pregnant” troubles from X-rays and the like.

That’s when children are born. If you want to, have unprotected sex just before ovulation; If you want to avoid this, carefully avoid any day that might be anywhere near the same time frame, plus a few days on either side for good measure. Better yet, use any of these awesome birth control methods – they work anytime.


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