Which pregnancy symptoms and signs are truly indicate pregnancy, and which just play tricks on your mind? Which symptoms can we see during the early pregnancy period? If we want to understand the process, we have to start from the female reproductive system and explain how it works.
The Female Reproductive System
What Is An Ovarian (AKA Menstrual) Cycle?
After puberty, the ovary cycles between a follicular phase and a luteal phase. The ovarian, AKA menstrual, cycle usually lasts 28 days, and at the midpoint of the cycle, the oocyte is released from the ovary in a process known as ovulation. Following ovulation, the follicle forms a corpus luteum, which synthesizes and prepares hormones to prepare the uterus for pregnancy. This is extremely important to understand before any discussion about implantation and pregnancy symptoms. [1, 2]
Hormones And Female Cycles
The ovarian cycle is hormonally regulated in two phases, where the follicle secretes estrogen before ovulation, and the corpus luteum secretes both estrogen and progesterone after ovulation.[1,2]
Hormones from the hypothalamus and anterior pituitary control the ovarian cycle, which is why it is possible to provoke an earlier period. It is a common situation for women that live or work together to start to bleed at the same time — phenomena, called Menstrual synchrony. This is all about the women’s brain activity, which has been scientifically proven. 
More About The Menstrual Cycle
Menstrual cycles tend to vary from between 15 to 31 days, and should not be confused with periods. The first day of the cycle is the first day of blood flow, known as menstruation or a period. FSH and LH are secreted on this day, beginning both the menstrual cycle and the ovarian cycle. Both FSH and LH stimulate the maturation of a single follicle in one of the ovaries, as well as the secretion of estrogen. At the same time, rising levels of estrogen in the blood trigger a secretion of LH, which stimulates follicle maturation and ovulation. It is interesting how estrogen and progesterone stimulate the development of the endometrium and preparation of the uterine inner lining for implantation of a zygote. If pregnancy does not occur, the drop in FSH and LH causes the corpus luteum to disintegrate and slough off the inner lining of the uterus. [1,2]
Fertilization And Cleavage
Fertilization has three functions [1,2]:
- Transmission of genes from both parents to offspring
- Restoration of the diploid number of chromosomes reduced during meiosis
- Initiation of development in the offspring
The three fertilization steps are contact between sperm and egg, entry of sperm into the egg, and fusion of egg and sperm nuclei. Then it is time to activate the development of the baby. It is also important to know that fertilization is the fusion of the sperm and egg, which usually occurs in the upper third of the oviduct.
So how does this process take place? In the beginning, about thirty minutes after ejaculation, sperm are present in the oviduct, having traveled from the vagina through the uterus and into the oviduct. This distance is crossed by the beating of sperm’s flagellum. Of the several hundred million sperms released in the ejaculation, only a few thousand reach the egg, which is still more than enough to impregnate it. In fact, only one sperm will fertilize the egg. [1,2]
Cleavage of the zygote begins while it is still in the oviduct, producing a solid ball of cells known as a morula. The uterine lining becomes enlarged and prepared for implantation of the embryo, and in this time human Chorionic gonadotropin (hCG) is secreted by the chorion. This is the first substance released in a woman’s body that confirms pregnancy and home pregnancy tests register this hormone. However, there are some early pregnancy signs we could notice before taking a home pregnancy test.
Most Common Early Pregnancy Signs And Symptoms
Missed period: This is a classic sign of pregnancy, especially if your cycles are typically on time. Once you have missed your period, it is time to take a home pregnancy test. Home pregnancy tests work by determining the amount of hCG present in the urine. The first urine of the day tends to have the most concentrated amount of hCG, and it will give the best results when detecting the small concentrations of hCG present in the early days of pregnancy: a home pregnancy test can tell whether you are pregnant with almost 99% accuracy, depending on how you use it. A missed period can also happen due to stressful situations, and as with many other signs of early pregnancy, the best way to confirm pregnancy is either with a pregnancy test or ultrasound at doctor's office. 
Morning Sickness: Morning sickness is a common early pregnancy symptom, and about half of all pregnant women experience some morning sickness, nausea, or vomiting. However, contrary to popular belief, morning sickness is not always limited to mornings; many women experience nausea in the evening, in the afternoon, and a substantial percentage of lucky moms feel sick all day long. Although it happens rarely, morning sickness can be extreme in some women. It’s recommended to contact your doctor if you become dehydrated because of morning sickness. Researchers have proven that morning sickness is linked to a lower risk of miscarriage, and that it protects the fetus against toxins and disease-causing organisms in foods and beverages. 
Sore breasts: Many women report feeling sensitive breasts. Some of them said it is the same way they feel right before they get their period. Breasts feel sore or even tingly, they may also feel fuller or heavier as well. However, this is one more sign that you may be pregnant because breast sensitivity is a common phenomenon in early pregnancy, and women may notice this symptom as early as 1 to 2 weeks after conception. Many mothers report this symptom begins to fade by the second trimester. 
Areola darkening: Along with sensitive breasts, a pregnant woman may notice a slight darkening of the areola. For those who don’t know, the areola is the concentric zone that surrounds the nipple. 
Vaginal discharge: This early pregnancy sign occurs because, in the initial days of pregnancy, mucous begins to accumulate around the opening of the cervix to form the mucous plug, which is supposed to be a barrier that helps protects the baby during its development. Because of this mucous formation, you will notice a kind of transparent to whitish normal vaginal discharge. It is important to know that infection could also cause vaginal discharge, although infection is accompanied with more symptoms, such as a burning sensation, foul smell, or itchiness.
Frequent urge to urinate: As the baby grows larger in the mother’s uterus, the space that once allowed for the expansion of the bladder will decrease, which will result in more frequent urination then ever before. Also, a woman may notice bloating similar to the usual pre-menstrual symptoms. 
Headaches and seeing spots: Because of the complex mixture of hormones coursing through a pregnant woman’s body, it is common for women to experience headaches more frequently during early pregnancy. 
Light spotting: Many women notice a bit of vaginal spotting. You could look for this sign at around eight to ten days after you last ovulated. This spotting or bleeding is lighter than a usual menstrual period and is a result of implantation. Spotting usually looks a bit different from your regular period. It tends to be light in volume and pinkish in color, as opposed to the deep and dark red color associated with normal menstrual bleeding. 
Constipation: Another sign of pregnancy is constipation, caused by certain hormones. The hormones that are released in early pregnancy days are relaxing your intestines and slowing the digestive process. 
Fatigue. Fatigue is one of the most common signs of early pregnancy — as many as 90% of women experience fatigue during early pregnancy — and unfortunately, pregnancy-related fatigue is not relieved by rest. A pregnant woman's body produces more of the hormone progesterone. Progesterone maintains the pregnancy and encourages the growth of milk-producing glands in the breasts. Pregnant women may notice fatigue as early as 1 week after conception because during pregnancy the body pumps more blood to carry nutrients to the fetus. 
When you notice these early pregnancy signs and symptoms, it is the right time to take a home pregnancy test. You can buy pregnancy tests in any pharmacy, with instructions on how to perform it correctly. If you get a positive result, this is a clear sign you are pregnant.
Some women might decide to have an abortion, especially those who aren't ready for a child. Should you be considering this choice, be aware that you will have more options earlier on in your pregnancy, and it is best to contact a medical professional to discuss a termination of pregnancy as soon as possible.
Pregnancy requires changing life habits the woman used to have. This means healthier living that excludes alcohol, drugs and certain medications. In addition, some pregnancies are hard to keep, so one must live under a restricted lifestyle regimen if one wants to carry the pregnancy to full term.