Comparison of Posterior Ocular Changes Between Singleton Pregnancy and Multifetal Pregnancy.

Study Overview
=================
Brief Summary
-----------------
It has been known that a pregnant women undergoes significant anatomical and physiological changes that mainly caused by hormonal and hematologic changes during pregnancy. Due to advance in reproductive medicine, the incidence of multifetal pregnancy was increased to 3% of livebirth. Multifetal pregnancies produce much more physiological changes in the body compared to the singleton pregnancies. Physiologic ocular changes during pregnancy are the followings Melanogenesis of eyelid and facial skin Cellular alteration of lacrimal and meibomian gland Increased corneal thickness and corneal curvature Increased lens thickness Increased retinal vascular density Increased choroidal thickness Decreased intraocular pressure -

Detailed Description
-----------------
From the literature review, there was only on study of ocular changes in twin pregnancies. Alim et al evaluated the choroidal and retinal thickness in singleton versus twin pregnancies. They included 20 single and 20 twin pregnant women in their 3rd trimester with 20-age-matched healthy non-pregnant women as a control group. They found that there was an increase in choroidal thickness in the 3rd trimester of pregnancies and it was prominent in twin pregnancies. There was a statistically significant difference in choroidal thickness between pregnant and non-pregnant women, but not significant difference between singleton and twin pregnancies. The mean retinal nerve fiber layer thickness was significantly higher in the twin pregnancy group than in the singleton pregnancy group. However, no study of retinal vascular density in twin pregnancies has been published before.

Official Title
-----------------
Comparison of Posterior Ocular Changes Between Singleton Pregnancy and Multifetal Pregnancy.

Conditions
-----------------
Twin Pregnancy, Antepartum Condition or Complication, Retinal Vascular, Choroidal Effusion

Intervention / Treatment
-----------------
* Device: Corneal tomography, optical coherence tomography and optical coherence tomography angiography


Participation Criteria
=================
Eligibility Criteria
-----------------
Inclusion Criteria: 24-37 years 30-36 weeks of gestational age clear ocular media written informed consent Exclusion Criteria: high risk pregnancies such as pre-eclampsia, gestational diabetic mellitus and asthma history of refractive error, spherical equivalent > 3 diopters history of retinal diseases such as central serous chorioretinopathy and retinal vascular occlusion history of intraocular inflammation or endophthalmitis history of intraocular laser treatment history of intraocular surgery

Ages Eligible for Study
-----------------
Minimum Age: 24 Years
Maximum Age: 37 Years

Sexes Eligible for Study
-----------------
Female

Accepts Healthy Volunteers
-----------------
Accepts Healthy Volunteers

Study Plan
=================
How is the study designed?
-----------------

Design Details

Primary Purpose: Other
Allocation: Non-Randomized
Intervention Model: Parallel Assignment
Interventional Model Description: age-stratified sample technique (2 age groups: 24-30 years and 31-37 years) ,twin pregnancy:singleton pregnancy:healthy non-pregnant women = 1: 2 : 2
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: multifetal pregnancy in the 3rd trimester<br>Corneal tomography, optical coherence tomography and optical coherence tomography angiography were performed in the 3rd trimester, 30-36 weeks of gestational age. | Device: Corneal tomography, optical coherence tomography and optical coherence tomography angiography<br>* Ocular investigations were performed in one time during 30-36 weeks of gestational age. Due to avoidance of diurnal variation, all examinations were done between 10 am - 12 pm.<br>|
| Active Comparator: singleton pregnancy in the 3rd trimester<br>Corneal tomography, optical coherence tomography and optical coherence tomography angiography were performed in the 3rd trimester, 30-36 weeks of gestational age. | Device: Corneal tomography, optical coherence tomography and optical coherence tomography angiography<br>* Ocular investigations were performed in one time during 30-36 weeks of gestational age. Due to avoidance of diurnal variation, all examinations were done between 10 am - 12 pm.<br>|
| Active Comparator: age-stratified healthy non-pregnant women<br>Corneal tomography, optical coherence tomography and optical coherence tomography angiography were performed. | Device: Corneal tomography, optical coherence tomography and optical coherence tomography angiography<br>* Ocular investigations were performed in one time during 30-36 weeks of gestational age. Due to avoidance of diurnal variation, all examinations were done between 10 am - 12 pm.<br>|

What is the study measuring?
-----------------
Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Choroidal thickness | Choroidal thickness was measured by optical coherence tomography. | 30-36 weeks of gestational age | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Retinal nerve fiber layer thickness | Retinal nerve fiber layer thickness was measured by optical coherence tomography | 30-36 weeks of gestational age | 
| Retinal vascular density | Percentage of retinal vascular density was measured by optical coherence tomography angiography | 30-36 weeks of gestational age | 
| Corneal thickness | Corneal thickness was measured by corneal topography | 30-36 weeks of gestational age |