Fetal Development Weeks 1 Through 4

See what's happening with your baby in the first month of your pregnancy.
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Week 1

Because the date of ovulation is often difficult to pinpoint, medical experts usually use the first day of your last period as the official beginning of the 40 weeks of pregnancy, and as the starting point in calculating your baby's gestational age.

Therefore, the extraordinary process by which your baby comes to life actually begins with an utterly ordinary event--your monthly period. During your last period before conception, the groundwork for pregnancy is already being laid. The previous month's uterine lining, called the endometrium, is shed, along with some blood, resulting in menstrual flow. Meanwhile, follicle stimulating hormone (FSH) kicks into gear, triggering the development of several ovarian follicles. Located deep in the ovary, these yellow bulbs each contain a single immature egg. As the bulbs grow, the eggs begin to mature. The follicles also signal the ovary to produce estrogen, a key hormone in bringing about ovulation.

Next:  Week 2

 

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Comments
Comments (48)
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KayMKoop wrote:

I thought I had AF, but it only lasted 2 days (and lighter). Then for 2.5 more days I just had some spotting. It's such an irregular thing for me as I usually have a 5/6 day period. The bleeding also came 2 days before I was expecting it, which was 11 dpo. I have a few preg. symptoms including headaches, being lightheaded, and irritability. Could I be pregnant? Fingers Crossed! :)

11/10/2011 04:03:28 PM Report Abuse
vmontez_24 wrote:

its been 10 years since i had my so, i was recwntly pregnant 2 times AND HAD A MISCARIAGE BOTH TIMES. WHY CANT I Carry baby to full term? i was 12 weeks along and miscaried and this last one one i was 8weeks. what am i doing wrong?

9/7/2011 07:53:30 PM Report Abuse
vargasamber1 wrote:

i am 16 and i think i am pregant and i display some of the symptoms and i am wondering if i do come out postive on the pregancy test if i should get an abortion cause i have my whole life ahead of me and the maybe baby daddy isnt talking to me and his 15 hows he going to help me raise a baby

7/3/2011 01:21:47 AM Report Abuse
mjarrie wrote:

Ok...help?! I have a 9 month old.... I have been nursing from the very begining. However, I got my first "post-baby" period on April 1st...then again on April 30th... was thinking I would get it on May 30th or 29th since it was a day early after the first cycle, yanno. BUT, IT NEVER CAME! Does anyone know if this is normal? To have irregular periods while STILL nursing? Or might I be pregnant AGAIN??!!

6/2/2011 06:12:56 PM Report Abuse
amartin21131 wrote:

I'm in a tough spot. I don't know if i'm pregnant. I thought i had started my period but only slight spotting for two days then nothing... it's been almost a week and i took a test about 3 days after that happened. It came back negative.

2/7/2011 05:30:14 PM Report Abuse
jerry2010bass1 wrote:

i have had mild like cramps after sex and stll no period. Its been 12 days since, my last cycle was on the 9th od dec. my first is going on 7. I WISH UPON A STAR THAT IAM

1/20/2011 11:57:48 AM Report Abuse
kystandingdeer1 wrote:

I think you are pregnant, I am 47 years old and I have milky white liquid coming from my breast. I took 4 pregenacy test and they came out neg. I also took ept and it came out neg. what do you think.rubydo422

1/16/2011 02:52:09 PM Report Abuse
mh541 wrote:

so I was supposed to start my period two to three days ago. I thought I was getting it, but it ended up being just a couple drops. I am on birth control and my boyfriend doesn't "get off" when we have intercourse. My breasts were really tender for about a week and a half. Now for the past three/four days I have been having this horrible back pain. Could I be pregnant?

12/13/2010 10:27:23 AM Report Abuse
puhuyesvac wrote:

Im only 14, going to be fifteen in a couple of days but, finding out is im really pregnant is a huge challenge. I was wondering should I tell my best friend who's been with me my whole life or my mom who i hardley hang around with? Or even my boyfriend cause i knw he'll freak out. I dnt really knw wut to do bt all i need is advice. This is my first time getting prego, plez if you have any suggestions or comments feel free..to step up.!!!

12/12/2010 04:33:02 AM Report Abuse
gjhbjhbjh1 wrote:

pleasee HELPP!!!!! I NOTICED SMALL RED LINES ON THE SIDE OF MY STOMACH AND A LITTLE ON MY BREAST LIKE 2. I RECIEVED MY PERIOD LAST MONTH. I HAVE NOT HAD ANY SORENESS OR BREAST SOAR NO NAUSEA AT ALL. NO SYMPTOMS. JUST THAT? WHAT CAN IT BE??? THANKS!!!!

12/10/2010 11:37:16 PM Report Abuse
gjhbjhbjh1 wrote:

kkk

12/10/2010 11:35:34 PM Report Abuse
gjhbjhbjh1 wrote:

mj

12/10/2010 11:35:28 PM Report Abuse
rochondra1 wrote:

i need help ok i missed my period for oct and nov came and no signs of period comn on and didnt come on and my period is regular and here it is dec and nuthn i took 3 pregnancy test and still nuthn can sumbody help email me at rochondra@gmail.com thanks

12/5/2010 08:35:20 PM Report Abuse
tanitasamuel wrote:

ok i need some help me and my husband had intercourse on the 26 and 27 of novenber and i came on my menstrual 4days early and i went off three days early i usualy last five to six days i have been sleepy more than usual certain smells bother me and craving salt and to top it all off my feet are swollen could it be a possibility i am pregnant

12/4/2010 11:28:45 PM Report Abuse
luvs2dance_06 wrote:

HELP! I am ttc my 2nd child My last period was 7/30 and they normally are 31 days So i was due to get my period 8/30 My period has not come yet a week ago i started to feel really sick to my stomach tired always moody and my boods hurt So i got 5 days early hpt and it was neg So i waited to see if I got my period then took a test 9/1 still neg I am still feeling all of those symptoms i just need some advice please help

9/2/2010 01:14:41 AM Report Abuse
cnichols123 wrote:

okay i have a question. i normally don't get my period due to my birth control. I was told before that my birth control could mess up the pregnancy test but i am not sure????? i keep feeling extremely tired and sick occasionally, i am getting a little fatter kinda but it feels like i am just bloated or that i eat to much junk food. please help me !!!!

7/15/2010 09:29:35 AM Report Abuse
Jenny143a wrote:

compalove11 the same thing happen to me too. I was asked to go back on Wed. to retest. If you have any news please anyone.. I still feel pregnant. I am hoping to be.I have been trying for 3yrs( naturally) and I dont want to get excited for no reason.

6/17/2010 05:47:21 PM Report Abuse
bradyandshanell wrote:

My daughter is 2 I misscarried 3 months ago I just found out I am pregnant again about 4 weeks in have some light cramping on my right side. I haven't been drinking as much water as normal cause it makes me sick. Do you think thatthere could be something wrong with the baby or am i just dehydrated.

5/26/2010 05:58:41 PM Report Abuse
tarashay wrote:

I have been trying for the past three years to have my first child i watch women who would rather not have a baby go through two even three pregnaceys any advise from anyone i do not know what i am doing wrong

4/17/2010 02:46:20 PM Report Abuse
Marilyn_luciano wrote:

I haven't been pregnant for 8 years since the birth of my last daughter. I have been trying for over a year now. I kind of forgot how it feels to be pregnant, but have been having multiple symptoms, from sore breast to moodswings. I got my period but it was shorter than usual with only one day of bleeding. I've taken 3 EPT's with a negative answer. Is it to soon to tell? It's driving me crazy!!!

3/17/2010 09:47:00 AM Report Abuse
compalove11 wrote:

So he decided to do a blood test in the hope that it was to early to detect. Please can some one tell me what to do. Also I have not missed my period yet it should come on the 16th of this month please help me pray. I cant face my husband with another disappointment he takes these worse then I do.

3/10/2010 07:36:02 PM Report Abuse
compalove11 wrote:

I had my daughter almost 6 years ago. Every since then my husband an I have been trying but with no luck. Every test is negative, I'm afraid to take another test. This week I have been feeling weird my breast have enlarged at least by 2% and they are so sore. I took an at home test and got a very light positive EXCITED! Then I went to my OBGYN today and got a NEGATIVE result? WOW not surprised.

3/10/2010 07:35:32 PM Report Abuse
kimfarmer79 wrote:

I have been trying for 9 years to get pregnant. I have pcos. I think i could be pregnant but not sure. I am scared to take a test. I have had lots of negative ones so now im scared to get a negative.I have been experiencing alot of heartburn for more than 2 weeks. I am a week late. My stomach is sore but not cramping. My breast are more sensitive and I feel nauseated til i eat in the mornings. Does anyone have any words of advice for me?

3/4/2010 10:04:59 AM Report Abuse
mystaphy wrote:

My period is usually due on the 3rd of the month and I had sex on the second. My period was 4 days late and shorter than normal. I have a 7 day period and this one only lasted 3. A week later my boobs started feeling like I need to pump but I'm not breast feeding anymore and haven't been for almost 5 years. I took a pregnancy test came back negative, two weeks later came back negative again. I think the test is wrong. Does it sound like I am right?

3/2/2010 10:33:24 PM Report Abuse
blueeyez32 wrote:

I never thought I would have another baby, but when my period was five weeks late I knew something was up. And guess what I am about seven weeks and loving it. All i am hoping for is a girl if not a healthy and beautiful baby. I will keep everyone posted!!!!! oh this will be baby number three!!!!!!!!!!!!!!!!!!!!!!

3/2/2010 01:19:39 PM Report Abuse
julia_140 wrote:

Had spotting once and was told that was normal, when you are in week 4. Husband on other hand thinks, it is just me being late as usual. Would like to have a baby before I am too old to have one.

3/2/2010 12:07:12 PM Report Abuse
TY51 wrote:

HAY

2/21/2010 01:19:14 AM Report Abuse
knoxamy wrote:

We've been trying nonstop for our 3rd. Iv'e been showing a bump, exahusted even though i sleep all the time, plus nauseated, peeing alott, can't stand some smells. 4 days till period is suppose to show up,,,,, I think, but am unsure, nervouse, can't get this overwhelming thought that I am....

2/18/2010 05:05:38 PM Report Abuse
barngirl32 wrote:

Okay,So im on the pill and ive missed three pills ( BAD I KNOW)and i had sex a few days. My breasts are fine. Some mild cramping and im EXTREMELY tired and just wanna sit down and eat...too early for a test. Any advice?

2/17/2010 03:29:01 PM Report Abuse
shygal_6187 wrote:

Hi Everyone. I am almost 23 and have been diagnosed with PCOS and am working on having my first child. I am having some symptoms of pregnancy but i have only been having intercourse this month about a week ago to today. I know for sure it would be too early for a test. Any one have any advice for me??

2/16/2010 05:26:58 PM Report Abuse
talden2594 wrote:

Period 1/21/10, Paraguard IUD removed 1/25/10, sex couple days before ovulating, during & after. Experiencing many pregnancy symptoms. Spotting brown color & mild cramps this am. Negative urine & blood test, however dr ordered blood test 1 already taken standard blood test. This one more sensative and it may be that it is too early in pregnancy to show. Desperate to become mom again! Anyone have same issues?

2/16/2010 02:52:06 PM Report Abuse
anonymous wrote:

rebecca, you may want to get a pregnancy test. I tested 5 days early and it was positive. My breasts are extremely sensitve, and im tired all the time. I will be 4 wks on feburary 8. This is my second baby. I knew i was pregnant with my second right away. As women we know our bodys, so listen to it and take a test. I hope the best for you and wish u luck!!!

2/6/2010 03:06:54 PM Report Abuse
beccal30 wrote:

I WOULD CALL YOUR DOCTOR

2/4/2010 01:06:43 PM Report Abuse
lauren.april.franklin wrote:

Hi.I have had a lot of cramping and sickness.But i havn't woken up and been sick.It's just been through out the day that i start feeling sick.I have been more tired than i have ever been.My breasts are fine.Everything i eat seems to come out right away.Been drinking lot's and still seem dehydrated.Feel pretty bloated.Someone please help me.Could this just be my period coming in a worse way,or am i possibly pregnant.I have not taken a pregnancy test yet because it's only been a few days.

1/3/2010 01:41:54 AM Report Abuse
triceh79 wrote:

Tammywhite4171 go see a doctor to be on the safe side

12/31/2009 07:43:36 PM Report Abuse
tammywhite4171 wrote:

HEY IM PREGNANT AN I HAVE BEEN HAVEN ALOT OF BLEEDIN 4 TWO DAY AN THIS DA TIME MY PERIOD WOULD COME ON DO I NEED TWO BE WORRING IF IM MISCARRAGE ARE NOT.......

12/31/2009 12:45:55 AM Report Abuse
noeloveme wrote:

i'm pregnant and i dont have any symptoms and i have not had my period in 3 month why

12/26/2009 03:41:28 PM Report Abuse
natashajohnson29 wrote:

hi i have 5 kids already & my tubes been tied for 3 years now, however i strongly believe that i am pregnant.I been nauseated & fatigue almost everyday.I also have very tender & swollen breast,my feet & hands has been swelling as well.Certain smells make me sick.I had my cycle this month but it was only for 2 1/2 days & it wasn't alot, usally I have my cycle for 5 -7 days. I also been having diahria along with all the other syptoms for about to 3 weeks now.

12/26/2009 10:33:36 AM Report Abuse
flybetxch wrote:

hello everybody im trying to find out if im pregnant or not . my period just came on but it two weeks late and before that i was eating everything that i could. for example : my mom would cook a whole meal i would eat that and 10mins later go eat McDonald and buffalo wing . i would have morning sickness but now i am on my period SOMEONE PLEASE HELP ME !

12/21/2009 11:45:58 AM Report Abuse
starlight200790 wrote:

hi my period last month and me and my friance was have sex and then in dece on the eight of this and i just noice that i didnt have a preiod so do you get baoling and gases so ya i have all those syptoms. 1 i have headaches 2 boatling 3 feeling sick 4 swllow of the breast and trenderness 5 dizzness and high warn presure

12/19/2009 09:01:23 PM Report Abuse
lil_miss_attitude101 wrote:

i'm pregnant and i have all the symptoms. I only puked once so far I'm so happy I'm having my first baby.

12/18/2009 03:48:08 PM Report Abuse
rebeccat10 wrote:

im trying to figure out if im pregnant or not. I have never been pregnant before so i have no idea..!! and i did that quiz and i have about 12 of the 13 signs!! my boobs are sore and seem very tense.. i havent yet had my periods and i have the strangest cravings!

11/30/2009 08:44:34 PM Report Abuse
lilbrowneyedgrl89 wrote:

ive taken a pregnancy test a couple of weeks ago and it came out negative but this past week i was supposed to start my period but it still hasnt come but ive been having the worst cramps. they're even worse than usual. they hurt so much im awoken out of my sleep at night. what could be causing this?

11/14/2009 05:44:45 AM Report Abuse
tracie3521921 wrote:

lotumala how old are you

11/10/2009 08:27:19 PM Report Abuse
lotumala wrote:

i am confused, i usually have my periods every 20 -24 days of the month i may have two periods twice a month and before my period comes my breast is alway very painful and full.also my tube was tied 13yrs ago after i had my second baby.my last period was oct 3rd. and have not seen my period as of today.i used the home pregnance test it was negative. my breast is not tender but a little full. what advice can you give me

11/8/2009 03:50:29 PM Report Abuse
jackig3 wrote:

im trying to figure out if im pregnant. this is only our first month trying, my period is late which is normal for me but i have 7 out of the 13 signs that are on here. and cramping is not normal for me between periods but the pregnancy tests are all coming back negaitive.

11/3/2009 06:39:35 PM Report Abuse
us3post wrote:

Take a pregnancy test. That is the best way to know.

11/1/2009 10:35:48 AM Report Abuse
ditsyiam7187 wrote:

im stuck tyring to figure out if im pregnant, i got my period but late. my breast hurt and thaats not a normal symptom for me when i get my period. i did gain some weight but i cant say if its because of not working for the past 2 months or i really might be pregnant.. . what do you think???

10/30/2009 09:58:16 AM Report Abuse
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