Beta Scores for Successful* Twins Pregnancies

Days Past Ovulation (What is this?)	Median HCG Level	Lowest HCG Level Reported	Highest HCG Level Reported	Number of women reporting a number for this day
10	23	5	289	15
11	60	13	1443	65
12	86	3	2583	200
13	148	5	4622	381
14	241	8	8270	693
15	376	11	14798	1496
16	563	18	3879	1884
17	833	12	6600	1910
18	1200	30	9289	1975
19	1698	40	12979	1870
20	2458	52	16384	1636
21	3563	70	23310	1402
22	4985	152	27554	1109
23	7064	107	36231	932
24	9189	138	47639	726
25	11792	177	62640	598
26	15039	227	82364	493
27	18910	291	108300	407
28	24297	374	203398	359
29	31106	480	394836	304
30	34497	995	189191	252

* Pregnancies are deemed successful if a heartbeat is detected.