All you need to know about early gestation.

All you need to know about early gestation.

Hello friends , welcome to another post, this time we starting already with Pregnancy. And, let me guess? you did a pregnancy test and is positive, that’s awesome, now pay attention because I will walk you through all the important things that you need to know about early gestation and your first appointment with your Gynecologist.

First of all, I want you to know that, there are several periods before we even see a viable pregnancy on Ultrasound, Those periods are:

Ovarian period: its 1 to 2 weeks after the first day of your last period , this is the period when ovarian follicles mature.

Conception period: its 3 to 5 weeks after the first day of your last period , this is the period where fertilization occurs .

early gestation

Embryonic period: its 6 to 10 weeks after the first day of your last period , is in this periods where a viable pregnancy is seen on ultrasound at about week 6 , this is the period where Embryo forms and the major organs develops.

early gestation

Fetal period: its 11 to 12 weeks after the first day of your last period . All major fetal development is already done and this period is all about fetal growth.

Fist trimester of pregnancy is defined as the 13 weeks following the first day of the last menstrual period (LMP).

Hormone measurements ( HCG ) : Urine pregnancy test can detect the presence of HCG at the level above 25 IU/L which corresponds to day 24 of a regular 28 day cycle.

In normal pregnancy serum HCG levels double approximately every 2 days and it is done with a blood test.

Once the HCG levels are above 1000–1500 IU, a vaginal ultrasound usually can identifies the presence of an intrauterine pregnancy.

An Ectopic pregnancy is suspected if the HCG does NOT DOUBLE in 2–3 days. If NO pregnancy is seen in the uterus by week 5 with an HCG levels of 1500 UI or more.

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early gestation, ovulation and implantation, early pregnancy

Important things to know about early gestation.

Now Let me talk a little about Miscarriages.

Miscarriages occurs approximately on 20% of early pregnancies.

Typical miscarriages symptoms are:

1. Vaginal bleeding.

2. Abdominal / pelvic pain.
However some miscarriages are asymptomatic.
Risk factors for early pregnancy miscarriages are:

1. Previous pregnancy losses.

2. Infertility treatments.

Miscarriages are classified in 3 different major categories:

Missed Abortion or Miss AB: Retention of gestational sac within the uterus following embryonic or fetal death, Absence of cardiac activity is detected on Ultrasound.


Ultrasound image of a gestational sac and fetal pole still seen within the cavity , The measurements of the fetal pole are usually smaller than the gestational age and NO heart beat is identified on Ultrasound.

Incomplete Abortion: Gestational sac is not seen on the uterus however the cavity still appears to be thick and blood clots and/or retained products of conception are still visualized inside the cavity.

early ultrasound

Ultrasound image of the cavity of the uterus showing No gestational sac and/or fetal pole but still some fluid , blood clots and debris are seen inside.

Complete Abortion: its diagnosed when the endometrial cavity appears thin and clean of products of conception after the bleeding.

early baby ultrasound

Ultrasound image of the cavity that appears to be clean and thin.

Ectopic pregnancy is defined as implantation of the fertilized ovum outside the uterine cavity.

ectopic pregnancy seen on ultrasound

Ultrasound image on an Ectopic pregnancy, the uterus was seen to the Left and the Left ovary to the right of the image and in the middle the ectopic pregnancy was clearly seen, now in some cases ectopic pregnancies can appears as a rounded mass instead of a sac with a fetus inside.

You might be interested in this post:
Normal first trimester ultrasound, scan at 6 weeks of gestation.
All about normal 7 week ultrasound.

Final thoughts:

This covers important aspects of the first visit , on early gestation Ultrasound can not see a viable pregnancy inside the uterus unless you are 6 weeks or more, the patients usually don’t know and get nervous when the pregnancy is not seen on the first scan.

The next post will be about Normal first trimester ultrasound , I hope to see you there, as usual thank you for stopping by.

Zadi. XO

Disclaimer: Due to HIPPA compliance and regulations all patient information is protected on this site. Also the information provided on my blog is designed to provide helpful information about the topic and are made with the best of my knowledge therefore is not intended to diagnose or treat any medical condition, For diagnosis or treatments on any medical problems consult your own physician. The author is not responsible or liable for any mistreated pathologies or wrong treatments.

Hi, I am Zadi, ultrasound tech, mom of 2 boys and a writer at heart. I write about pregnancy and motherhood!