First week of pregnancy - when does it really start? Are there any symptoms during the first week of pregnancy? How to recognize pregnancy in 1 week? Can you be sure you are 1 week pregnant?
Such questions are asked on many forums for mothers-to-be. Before we answer them, we will explain why the first week of pregnancy is a conventional concept, and the woman may not be (and most often is not) pregnant at that time.
First week of pregnancy: when does it start?
Pregnancy is generally assumed to begin before the egg is fertilized. According to Naegele's method, the most commonly used method for determining gestational age, the first week of pregnancy is counted from the start of the last menstrual period, meaning the beginning of the last menstrual cycle. Fertilization occurs during this cycle – determining its date, although possible, is not medically significant (unless, for example, in vitro fertilization is involved ). During menstruation, it is unknown whether the cycle will result in pregnancy or not, so the onset of pregnancy, especially its first week, is dated backward, and its course and symptoms can only be analyzed after the fact.
What does week 1 of pregnancy mean?
Since it's the last menstrual period preceding conception, not conception itself, that marks the beginning of the first week of pregnancy, this week can be described as the "final countdown" to actual pregnancy —regardless of whether it's the final stage of planning or a time when a woman's body prepares for pregnancy, though she may not necessarily be aware of it. During monthly bleeding, the lining of the uterus is shed to create the conditions for the subsequent development of pregnancy.
The entire menstrual cycle, which begins with each period, lasts approximately 23-35 days. During the first week of the cycle, theoretically the first week of pregnancy, so-called Graafian follicles containing immature egg cells begin to mature in the ovary. One (or several) of these follicles will be released during ovulation, approximately mid-cycle. Fertilization can then occur – the egg is viable for 5 hours, and sperm for up to five days.
1st week of pregnancy: calculations and reality
Maintaining good health and maintaining a balanced hormonal balance promotes regular cycles, making pregnancy planning easier. However, in reality, a woman's cycle length fluctuates depending on various factors, such as illness, travel, and stress.
All of this means that ovulation and possible fertilization can occur several days or even a dozen or so days after menstruation . In very rare cases—with irregular or short cycles and long periods—fertilization occurs during menstruation, i.e., in the first week of pregnancy.
That is why the actual date of delivery is calculated not only based on the last menstrual period, but also confirmed by ultrasound of the first trimester, and in the following weeks, also by ultrasound of the second and third trimesters.
1st week of pregnancy: symptoms typical of menstruation
Menstruation, which marks the beginning of the first week of pregnancy, makes it difficult to associate symptoms observed during this time with pregnancy . Abdominal cramps and pain, back pain, headaches, and lethargy can all resemble the first week of any other menstrual cycle.
More or less accurate calculations regarding the moment of conception can be made later, thanks to an ultrasound, which allows for determining the actual age of the fetus. At that time, you can also look back and recall how you felt during the first week of pregnancy. However, when it comes to gynecological symptoms in the first week of pregnancy, which begins with the date of your last menstrual period, there is no significant difference in relation to how a woman felt earlier.
Can pregnancy symptoms occur in the 1st week of pregnancy?
In many forums related to motherhood, nausea or increased breast sensitivity are mentioned among the first signs of pregnancy. However, these are not usually symptoms of pregnancy - they are usually absent in the first week, but they appear later, at least one week after conception. Only in those rare cases, when the egg is fertilized during menstruation, the first nausea or breast hypersensitivity may also occur in the 1st week of pregnancy.
More often than the symptoms of the first week of pregnancy, the feelings or emotions associated with it are mentioned – joy, fatigue, euphoria, disorientation or anxiety.
Unanswered question, or how to recognize pregnancy in 1 week?
Unfortunately, there's no satisfactory answer to the question of how to recognize pregnancy in the first week, although the topic is discussed on almost every motherhood forum. During or immediately after your period, when conception is about to occur or has already occurred, there's no point in taking a pregnancy test. A visit to a gynecologist won't help either, as at the current level of medical knowledge, there's no method for detecting pregnancy in the first week. Therefore, you need to be patient and wait until your body signals it naturally or until you can use a test . Most doctors advise waiting at least a month before your first appointment.
1st week of pregnancy: supplementation and testing
During the first week of pregnancy - even if it is not recognizable because it is not yet fertilized and has no symptoms - steps can be taken to help your body prepare for it. Already then, the uterine mucosa is prepared to receive the fertilized egg and the further development of the pregnancy. Therefore, it should be properly nourished and moisturized, and the future mother's diet has a big impact on it.
- In addition to healthy eating and discontinuation of stimulants, an appropriate dose of exercise is recommended.
- The Polish Society of Gynecologists and Obstetricians recommends that take it already 12 weeks before pregnancy folic acid at a dose of 0,4 mg per day. The first week of pregnancy, understood as the date of the last menstruation before pregnancy, is therefore the last call to start supplementation, if the woman has not decided on it earlier. During pregnancy, the demand for folic acid increases threefold, so even a healthy and balanced diet may not provide the future mother in the required amount. Folic acid deficiency threatens with congenital defects of the fetal neural tube, and supplementation started early enough and continued throughout pregnancy reduces the risk of their occurrence by 70%.
- At this stage, you can do blood testto rule out anemia and correct any deficiencies in a timely manner, and urinalysis - for the presence of protein or ketone bodies. A general urinalysis is used to rule out infections, for example. However, it is routinely not recommended to do these tests before you become pregnant.
- Pap smear - recommended once a year as part of the prevention of cervical cancer - should be done early in pregnancy, unless it has been performed recently (NFZ reimburses the cytology once every 3 years).
- It is advisable to do this once a month breast self-examination - palpation should be performed by a doctor during a routine check-up visitj. It is also worth performing an ultrasound of the breast.
- During the first trimester of pregnancy X-rays are not taken, including teeth, therefore diagnostics and serious dental procedures should be planned in advance, and before root canal treatment or anesthesia, inform the dentist about a possible pregnancy.
- Beauty treatments, most notably those involving retinoids, as well laser hair removal, it is recommended to plan ahead of a possible pregnancy.
It's therefore worth considering both supplementation and necessary diagnostics when planning a pregnancy – also due to subsequent restrictions on certain treatments and procedures. To protect against potentially dangerous infections, vaccinations against rubella, mumps, chickenpox, hepatitis B, pertussis, as well as influenza, pneumococci, and Covid-19 are recommended before pregnancy.
Consultation:
Ph.D. n. med. prof. IMID Tadeusz Issat - Head of the Obstetrics and Gynecology Clinic at the Institute of Mother and Child;
Maria Krowicka-Wasyl – resident physician during specialization in gynecology and obstetrics, Clinic of Obstetrics and Gynecology at the Institute of Mother and Child.
